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73-87 Chevy _ GMC Trucks => Electrical => Topic started by: 1967KaiserM715 on October 28, 2017, 04:08:06 PM
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Done a few searches, not really finding what I think I need to find, so here it goes-
Truck is a 1985 GMC K1500 6.5 TurboDiesel, original harness for most part, any extra wiring is tapped into separate circuits.
My problem currently lies with the wiper system, it has the delay wipers in the stalk on steering wheel. They did work all right at the beginning, but with the past few heavy rains, sometimes they work, sometimes they don't (like not moving in any setting.) And now the off don't work, to get them in the "down" position I have to play with the mist setting, as turning to off does not work at all.
Delay setting seems to have completely stopped working, seems to only really have the low setting in delay. And when they work, low and high seem fine.
I have looked at power at motor, seems to be fine there, but of course when I'm testing the wipers "work" and don't randomly stop.
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So take the delay module out of the equation, simply disconnect it and connect the two connectors together. Does low and high speed work normal after you do this?
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So take the delay module out of the equation, simply disconnect it and connect the two connectors together. Does low and high speed work normal after you do this?
Been very busy, but disconnecting delay module, low and high still work.
There seems to be no "park" setting for the wiper, which typically means a bad board on the motor.
Plus I'm not sure how mist is supposed to work, I have to hold it in mist and guess when it's close to down before releasing, otherwise it will stop anywhere.
With the way things are somewhat working, I'm guessing I have at least 2 separate issues I need to address.
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this sounds almost exactly like the symptoms my 88 had, i stated having to use mist to shut off the wipers and deal with a randomly failing delay but lo and hi worked fine, i got a replacement wiper delay module and no more issues. Mist when operating properly should give you a single sweep (or continuous as long as the switch is held) of the wiper blades and then park them back where they started, i know there is a park switch/sensor in the wiper motor that controls where the wipers park but i don't really know much about that. As for bypassing the delay module i did not know you could just plug those two connectors together without the delay module
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You have the correct wiper motor and the washer pump in the jug?
Clean the connections at the motor, also pop apart the module and clean the connections. If the motor still won't park, replace the motor.
As for bypassing the delay module i did not know you could just plug those two connectors together without the delay module
That's all there is to it
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Yes, everything is correct, it worked fine the first few times, then got steadily worse, cleaning connections was actually my first step.
I'll pop the covers off and clean internal connections next. Snow is starting to fly, although I picked up a '91 K2500 as a winter beater, just finished rebuilding the 4l80e in that.
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The terminals have a tendency to be loose in the connectors at the motor so push the wires in snugly as well. I just had one with extremely high resistance at all of the terminals on the lower connector. I don't believe they make that pigtail so I just put new wires and terminals. Made a big difference.
PS The older I get, the more I hate snow and the winter. Please don't send the snow down to me.
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I used to have a similar issue with my 86 GMC. Mine would break the wires in the column because of the tilt wheel. Sometimes it was just the wipers, sometimes the cruise control and sometimes they took turns not working. I would replace the turn signal stalk and it would work fine for a while.
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The only wires in the stalk are for the cruise control is equipped.
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It’s all on the same stall on that truck.
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My memory could be failing me but I changed the stalk for both reasons and fixed my problem. It’s been a long time so maybe my memory isn’t completely accurate?
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Unless it has cruise, no other wires are in the stalk.
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Right on.
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Unless it has cruise, no other wires are in the stalk.
Yup just tightened the tilt column in my 84 and the signal switch is attached to the stalk by a little metal arm and screw inside the upper tilting part of the column
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Back at this, don't know how I got the deal, but got an AC-DELCO wiper delay module for cheap- 25 bucks free shipping through Amazon, it must have been one of their lightening deals, or a warehouse buy, cause I couldn't find it after. That did not solve it, nor did cleaning contacts.
To refresh, there is no delay of wipers, as soon as you enter delay it wipes with the same speed as low, low and high do work. There is no off and park function. Mist mode does not work, you need to hold the stalk, moving stalk to mist will move the wipers, but letting go stops wipers immediately, I have to move into mist and hold until the wipers are low on the windshield before I let go to stop the wipers.
I may have some time to actually work on this, as I lost my rear driveshaft on the way to work, no apparent cause, but slip yoke is seized to output shaft, broken ear on that, both straps on axle, but missing one u joint cap.....but anyways, back to wipers.
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Did you replace the wiper motor?
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I have not, should that be my next step? I don't really want to spend the time or money just replacing parts, but I guess there comes a time it must be done. I only did the delay module 'cause it was a good deal, and easy to swap.
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I know this post is a little old, but this issue is so common, I figured I post my findings on my 86 k10.
My problem was one speed for wipers and no delay. Wipers would run until I turned the stalk to the mist setting.
I first checked the circuits for potential shorts. It seemed ok. I then cleaned the connectors. No change in the wipers.
I pulled the pulse module apart and found a relative simple circuit with a few capacitors in it. Since caps tend to go bad over time, I replaced them. Still no change.
Went to the junkyard and found a module off a 89 Suburban that was in real nice shape. No change.
At this time, I was getting frustrated. My high beams didn't work, blinkers wouldn't cancel on their own, horn didn't make noise, and my wipers weren't fully functional. I decide to rebuild my steering column. I replaced all electrical components with AC Delco parts all new including the pulse module. Put it all together, everything works except for the wipers. However, my wipers would turn on as soon as I turned on the ignition and would not turn off.
I sent the new pulse motor back and got a replacement. Back to the original symptoms.
I then decided to replace the wiper motor. This gave me both a low and a high speed, but still no delay. I would still have to rotate the wiper switch backwards to the mist position to cancel the wipers.
I then took my old wiper motor apart and cleaned off the electrical connections for the park position. This would let the wipers return to park without using the mist position and also give me 1 cycle of delay before the wipers would wipe constantly.
Hoping I was getting closer, I returned the wiper motor and got another one. It now works the same as the motor that I cleaned, but no real delay. Only 1 cycle and then constant wiping afterwards.
I checked all of the wiring again and could not find any shorts to ground or opens or any abrasions in the physical wires.
My conclusion is that this system is a piece of crap and the replacement parts are just as crappy. I cannot say with any certainty that all of the parts that I have put into this problem are actually working as designed even though they are brand new. I have decided that it's not worth my time or money to pursue it any further. >:(
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Well wouldn't the world just be dandy if everything were easy and could be solved by simply replacing parts?
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Nice. Thanks buddy! ;)
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Considering its been a year, my wipers still do not work correctly. And its gotten worse... Truck is a 1985 GMC K1500 With intermittent wipers.
My Symptoms:
Wipers have NO Delay feature
Wipers do not turn off when switched to OFF, only when switched to "Mist Function"
Mist does not function correctly, must hold for wipers to move, when released wipers stop(they do not Park)
When in "delay" only move at low speed. stays in low speed when in Low
High Speed sometimes does not function.
Also more frequently now, wipers fail to stay on and will stop mid-sweep sometimes.
Some things I've done:
Made sure motor wasn't grounding internally, via this test on post #7 in this thread- http://forum.73-87chevytrucks.com/smforum/index.php?topic=10154.0
Applying 12v to power in and grounding the High and Low circuits on the motor, the motor functions as it should.
Removed the delay module-this of course gets rid of delay, but still will not allow Wiper motor to park, must still go to "mist" to stop wipers
I have removed and cleaned all connections, verified grounds.
I attached a two New motors to the system, not a full install, both motors did the same thing as the original. I added ground wires to the motor body, with no change.
tried 3 different pulse boards, 1 new, two used, all function the same.
tried two new switches-not a full install, I just plugged both switches into the harness and left them hanging on the floor.
Just the last day I've been doing continuity and power checks. Some things I've noticed. when applying 12v+ to the wiper motor, my test light lights up when probing the low and high circuit. Normal??it does it on both motors I have.other then that I haven't noticed any abnormal continuity issues, I'm going to redo the tests right now, but I would really like to get some input on this.
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Concentrate on the "no park" issue first. With all wires connected, ignition switched ON, wipers switched OFF, and wipers in the "up" position, use an incandescent test light clipped to a verified good ground and probe both gray wires at the w/w motor. Are both gray wires live? Probe the blk/lt blu wire at the w/w motor - is it live? Reconnect the test light so it is clipped to B+ and reprobe the blk/lt blu wire. Does the test light illuminate?
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Concentrate on the "no park" issue first. With all wires connected, ignition switched ON, wipers switched OFF, and wipers in the "up" position, use an incandescent test light clipped to a verified good ground and probe both gray wires at the w/w motor. Are both gray wires live? Probe the blk/lt blu wire at the w/w motor - is it live? Reconnect the test light so it is clipped to B+ and reprobe the blk/lt blu wire. Does the test light illuminate?
Both grey are live with wipers up, ign on, wiper switch off.
Blk/lt blu does not light with test light connected to ground.
Blk/lt blu illuminates when connected to a B+ source.
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Regardless of the number of wiper motors you've tried, the "park" problem is the park switch inside the wiper motor. The gray wires testing live indicates that the wiper motor circuit is complete all the way up to the two-wire park switch connector. Both tests of the blk/lt blu wire indicate that the park circuit is complete between the park switch and ground via the wiper switch. That leaves the park switch and its connections inside the w/w assembly as the culprit causing no park. A faulty park switch will also cause "mist" to malfunction and not park.
For the delay issue, unplug the wiper switch from the delay module and use your ohmmeter to measure the resistance through the brown wires of the w/w switch. Measure the resistance across the full sweep of the delay knob on the turn signal stalk and report your findings.
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Regardless of the number of wiper motors you've tried, the "park" problem is the park switch inside the wiper motor. The gray wires testing live indicates that the wiper motor circuit is complete all the way up to the two-wire park switch connector. Both tests of the blk/lt blu wire indicate that the park circuit is complete between the park switch and ground via the wiper switch. That leaves the park switch and its connections inside the w/w assembly as the culprit causing no park. A faulty park switch will also cause "mist" to malfunction and not park.
If you're skeptical and wish to verify this ^^^^, with ignition ON, wipers OFF unplug the two-wire connector (gry and blk/lt blu pair) from the w/w motor and jumper the wire pair together, bypassing the park switch. Do the wipers run on low speed?
Yes - the park switch is missing or faulty OR there is a continuity problem through the connector terminals.
No - there is excessive resistance in the gry or blk/lt blu wires and further tests are needed.
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Regardless of the number of wiper motors you've tried, the "park" problem is the park switch inside the wiper motor. The gray wires testing live indicates that the wiper motor circuit is complete all the way up to the two-wire park switch connector. Both tests of the blk/lt blu wire indicate that the park circuit is complete between the park switch and ground via the wiper switch. That leaves the park switch and its connections inside the w/w assembly as the culprit causing no park. A faulty park switch will also cause "mist" to malfunction and not park.
If you're skeptical and wish to verify this ^^^^, with ignition ON, wipers OFF unplug the two-wire connector (gry and blk/lt blu pair) from the w/w motor and jumper the wire pair together, bypassing the park switch. Do the wipers run on low speed?
Yes - the park switch is missing or faulty OR there is a continuity problem through the connector terminals.
No - there is excessive resistance in the gry or blk/lt blu wires and further tests are needed.
Wouldn't be the first time I've gone through several "new" parts, I'll double check with this test to confirm though.
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Check to make sure that the windshield washer pump on the fender is plugged in and the pump is operational. You wouldn't think that has anything to do with the operation of the wipers, but it does trust me.
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Assuming I've read my multi-meter correctly, start of delay sweep is .625 Mohm, end of sweep is about 1 ohm.
According to park switch test, it is the switch or faulty connections.
Washer works.
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(http://i123.photobucket.com/albums/o317/jjsabol/wiperwiring-1.jpg)
The procedure for "Wiper Will Not Shut Off"
Ignition switch is on - wiper switch is in the off position. Disconnect the wiring from the wiper terminals 4 and 3.
If the wiper stops: Repair the wiper motor (replace the park switch Assy)
If Wiper still runs continue on
Remove wiring from wiper terminal 19, 18, 17 connect 12v + to wiper terminal 19 only
If wiper doesn't run: locate and repair the ground condition in the wires from the wiper terminals 18 or 17 to the wiper switch.
If the wiper still runs: Repair the wiper motor (look for internal Ground condition in LO or HI Brushes)
According to this, if the wiper still runs with the park switch removed, there is likely a short in the low or high speed circuit. Using a fused test light, I probed the low and high connection at the motor. I get full brightness on power in(obvious), I get very dim light when probing the low side(wipers on low) and a a slightly brighter(half brightness) light when probing high(wipers still on low) Wipers have appeared to completely stop working on high now.
This was actually that grounded motor test I did earlier, but I guess I wasn't really paying attention when I wrote my previous post, and neglected to include the results.
**Accidentally just hit post, but with that, I still found no continuity to ground(with the exception of the black wire on truck side of pulse-board) on any wires. and I found no continuity between any other wires, all wires disconnected from motor and pulse-board.
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According to this, if the wiper still runs with the park switch removed, there is likely a short in the low or high speed circuit.
DID the wipers continue to run with the w/w switch OFF, ignition ON, gray & black/lt blue pair disconnected from the w/w motor? Or did it run only when you jumpered the gray to black/lt blue?
Using a fused test light, I probed the low and high connection at the motor. I get full brightness on power in (obvious), I get very dim light when probing the low side (wipers on low) and a slightly brighter (half brightness) light when probing high (wipers still on low) Wipers have appeared to completely stop working on high now.
If I understand you correctly, this ^^^^ is expected. Bear in mind, the w/w motor is powered whenever the ignition is switched ON. The w/w switch controls the ground path. As long as power is applied to the motor and the w/w switch is OFF (the ground path is open), a test light used to probe the motor leads will register the applied power and illuminate at full brightness on the I+ side of the motor while illuminating relatively dimmer on the "ground side" of the motor. The relative dimness between the high- and low-speed motor connections is due to the resistance introduced through the motor windings - the high-speed windings have less resistance than the low-speed windings, so the test light is brighter when connected to the high-speed lead.
On the other hand, when the ignition is switched ON and the w/w switch is set to low, grounding the gray low-speed wire, a grounded test light probing the gray wire should extinguish.
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DID the wipers continue to run with the w/w switch OFF, ignition ON, gray & black/lt blue pair disconnected from the w/w motor? Or did it run only when you jumpered the gray to black/lt blue?
Continued to run after turning switch off, leaving ign on, then disconnecting grey &blk/lt blu wires
If I had the ign on, and switch off (but not previously on) jumping the wires would run the motor.
I'll have to verify the test light tomorrow, I may have been in delay, not on low, if that matters. It was very dim, had there been more light (hood blocks a lot) it might not have even been noticeable.
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Continued to run after turning switch off, leaving ign on, then disconnecting grey & blk/lt blu wires
The only way for this to have occurred is if the gray (ckt 91) or purple (ckt 92) wires were grounded either through the w/w switch, the delay module or arcing to chassis.
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I assume since it does it without the pulse board connected as well, it's either the switch or the truck side.
Is it possible to just run two wires from the switch connector straight to the motor to bypass the truck side? All the other wires should just be part of the pulse or washer system right? And one to ground.
That would, in theory, narrow it down to the switch or faulty wiring on the truck side, depending on the results. Correct?Continued to run after turning switch off, leaving ign on, then disconnecting grey & blk/lt blu wires
The only way for this to have occurred is if the gray (ckt 91) or purple (ckt 92) wires were grounded either through the w/w switch, the delay module or arcing to chassis.
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You do have an interesting problem. Have you been referencing the 1985 wiring manual (http://www.73-87chevytrucks.com/techinfo/7387CKMans//Wiring/ST_352_85_1985_Chevrolet_GMC_Light_Truc_Wiring_Manual_CK_10_30_Only.pdf#page=9) during this process? It will benefit you to do so if you haven't. As long as this problem has persisted, trying a different approach seems overdue. I think you are on the right track.
Sometimes it's prudent to establish your own "knowns" and progress from there. Purge some confusion from the game so to speak. You know the park switch is a problem. Procure a wiper motor and, using jumpers and the factory wiring schematic, verify its operation on the bench before installation. Once you know you have a fully functioning w/w motor, you can eliminate that as a variable and install it. Next, verify all of the ground connections back to the battery negative post (i.e., wiper switch to harness to cab, cab to engine, engine to B-). This can be accomplished rather easily with a voltage drop test. Then establish your own circuits using jumpers directly to the switch, bypassing the delay module and factory wiring, as you suggested. I think if you take a systematic approach, avoid assumptions and prove the circuits as you progress, you'll resolve the issue fairly efficiently. You will need to substitute jumpers for the white (I+), black (B-), gray (low), purple (high), and black/light blue (park) wires. Ignore the pink (washer) and brown (delay rheostat) wires.
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Well I think the truck just hates me,
First step I took was to verify a good working motor, making sure the park switch functioned. All done on the bench with a separate battery. I used a spare wiper switch, and using alligator clips, and some spare W/W motor connections, I verified the motor functioned as it should, and that that switch was good. I then took it a step farther and attached a delay module and verified all still worked as it should. Everything is looking good, I have two good motors, a good delay module, and a good switch.
Next step was a ground voltage drop test, nothing more then .5volts drop at any connection.
so from there, I then plugged in a Good Motor to the truck, and without really thinking about it, just tested it, Ign on, and using the switch and delay module(untested) already in the truck, I checked the function of the motor....Everything seemed to work as it should, mist allowed one rotation, delay worked, turning to off would park the wipers....
I'll mention that at this point everything was original as how it came on the truck, original switch, original Wiper motor(but bench tested and verified OK) and original Delay board. I am now thoroughly confused, and slightly angry that everything is working as it should, without me really changing anything. I wiggle some wires with the wipers in a delay, nothing seemed to cause any issues, off would still work, mist, etc. So I use my bench tested switch and delay module, hook those up to the truck and same thing, everything working as it should.
So Final(just kidding) step, I install the wiper motor, all connections are put together, start wipers......NO Delay, NO Mist Function, NO Off/Park. I start wiggling all the wipers, checking all the connections, I then Use the bench tested switch and delay module, same thing, no Delay, no Mist, no Park. I forget to shut off wipers and leave them in Slow Delay, walk away to grab my multi-meter and test light. By the time I get back(2 minutes tops), the wipers are stopping and then one sweep, stop, sweep, stop and so on. So as I continue to stare, they pause at the Top of the sweep....and stayed there much longer then the normal delay I was just watching. they did finally move again, but at this point there is no delay, they move in a continuous sweep, and the Off function of course isn't working.
So I use the test light an multi-meter, I'm getting full power in(12.3v) grey low speed is at 7.6v, same with high speed purple. one end of multi-meter is attached to ground. test light doesn't really tell me much.
Now, here's the interesting part, I found if I took my test light and applied light pressure to the park switch arm(the piece that rides on the gear) the motor functions as it should, applying the test light to the grey wire at the park switch did nothing, only when I applied pressure to the switch arm. Its not much pressure, and really only is applied when the arm rides up onto the cam.
So yeah, 4 hours well spent today....
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Most common problems with these wiper systems are compounded or stacked issues. High resistance especially near or at the connector for the motor, the motor itself and connections at the module are the main points of high resistance. All it takes is a little bit of resistance and pinpoint tests become a cat and mouse game. As soon as you unplug or wiggle or backprobe connections the path of least resistance changes and the mouse moves to a new place. I would recommend repairing or replacing the pigtails at the wiper motor and disassembling and cleaning the connections at the module.
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Most common problems with these wiper systems are compounded or stacked issues. High resistance especially near or at the connector for the motor, the motor itself and connections at the module are the main points of high resistance. All it takes is a little bit of resistance and pinpoint tests become a cat and mouse game. As soon as you unplug or wiggle or backprobe connections the path of least resistance changes and the mouse moves to a new place. I would recommend repairing or replacing the pigtails at the wiper motor and disassembling and cleaning the connections at the module.
I was going to actually start today by replacing the park switch connector, as so far it seems everything is revolving around that(no mist, and no delay), the more I thought about it, the more its seems there is a break somewhere along the wire run for the blk/blu park wire.
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I replaced the park switch connector, by splicing in a used connector to the old harness near the junction block. That seems to have solved my problem, everything seems to be working as it should right now. I'm going to use the truck for a few days and see if the issues pop back up.
There doesn't seem to be anything visibly wrong with the old connector, but I do recall cleaning off a fair bit of corrosion when I first started having problems.
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I've used the wipers several times now, and there seems to be no issues now. Replacing the Connector End for the Park Switch on the Wiper Motor appears to have solved the issues.
Many thanks to bd and VileZambonie for their help and guidance, and to all those that also helped.
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Happy to hear you got it solved!
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Good deal!