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73-87 Chevy _ GMC Trucks => Electrical => Topic started by: JohnnyPopper on September 27, 2023, 12:00:02 am
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Notice my turn signal indicator in the cab stopped working on the left side.
I looked and the front blinker/parking light wasn't working. Parking light worked.
Naturally bought new bulbs but that did not fix the problem.
Noticed the side marker would blink out of phase with the front bulb (Right side)
When the left side blinker/parking bulb was removed, the side marker would blink strongly, and the turn indicator on the dash would follow.
With the front bulb installed it would not, noticed that the side marker dimmed and would not blink.
Cleaned the ground in the light fixture, DeOxit all connections, no difference.
Any help would be appreciated.
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Not sure what is going on. Hope it isn't a turn signal switch issue. I do know that it is normal operation for the side marker and front turn signal to flash opposite of each other in these trucks.
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Good thing you know how to use hand signals! ;D
Of course, if no one else does, it won't do you any good. >:(
The front side markers are connected between the park and turn signal circuits. So the 194 bulbs ground through the park/turn lamp filament(s) that are not energized.
Are the symptoms the same regardless of whether the park lights are ON? Is the left 1034/1157 bulb inserted 180° out?
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Right?!? They look at me like I'm a fool with my left arm out!
Not 180 out.
When I have the 1157 out, the 194 blinks.
When I install it, it stops, as if the higher load bulb is sucking all the power?
Thanks for the reply.
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When I have the 1157 out, the 194 blinks.
When I install it, it stops, as if the higher load bulb is sucking all the power?
This ^^^^^ I understood. But does it make any difference whether the park lights are ON or OFF?
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No it does not. On or off the front blinker or turn indicator does not turn on. Rear blinker works.
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I'm fairly confident the left front park/turn lamp has an open ground. If you have a voltmeter or incandescent test light, a few quick checks would verify or disprove that idea. With the left turn ON and the park lights OFF, clip to B- at the battery and probe the brown wire feeding into the left front park/turn lamp. If you discover voltage or the test light illuminates even dimly while probing, the lamp ground is open.
Try cleaning the socket using a socket brush (image) then disassemble and burnish the sheet metal ground to the radiator support. To verify proper grounding of the radiator support, clip to battery B- and probe the sheet metal support with the headlamps ON. Any measured voltage indicates poor grounding of the sheet metal.
Edit: added image.
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I'm on it, thanks bd!!!
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Well it's more bizarre than I can express.
With the blinker on, there is 1-2v on the blinker blade, there is .02 on the parking blade. Both jump with the blinker action.
When the parking lights are on, the parking blade sees 12v with the same fraction of a jump, while the blinker blade pulses between 4-7v.
With the blinker on, parking light off, the side 194 does nothing. With them on, it blinks brightly.
I found the the cab to motor strap was not connected, broken. replaced with one that I tied to ground cable at the alternator.
Burnished two ground points on the core above each headlight along with the grounding point of the negative cable at the alternator.
Created a strap between the core and the left fender.
Used DeoxIT at all points, after cleaning with brake cleaner.
Still no go!
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...With the blinker on, there is 1-2v on the blinker blade, there is .02 on the parking blade. Both jump with the blinker action.
When the parking lights are on, the parking blade sees 12v with the same fraction of a jump, while the blinker blade pulses between 4-7v...
I'm not clear on your meaning. I'm supposing that you used a DVM to measure from B- at the battery: 1) to the park lamp contact in the base of the bayonet park\turn socket and 2) to the turn signal contact in the base of the bayonet park\turn socket, initially with the turn signals flashing, park lights OFF and then with the turn signals flashing, park lights ON. Is this correct?
Repeat the checks using a test light. A DVMs response time may not be quick enough to register peak voltage on a pulsing circuit.
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Another way to approach the diagnosis is to substitute a temporary jumper for the turn signal flasher. Flip the directional signal stalk to left turn then use your DVM or test light to determine where voltage is in the circuit and where it isn't, w/o being distracted or misled by pulsing voltage.
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Great idea, will try that. ;D
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I know my brothers 79 CJ Jeep had some issues with low power to park lamps, blinkers not working. He just had all the wiring done. I looked over and over and for whatever reason reversed the wiring on one of the park lamps and everything worked again. Don’t know if a CJ’s wiring or ground schematics are similar just throwing out ideas.
Sent from my iPhone using Tapatalk
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Thanks buddy,
I did just have the two front fenders replaced as the others rotted out so bad the end on drivers side fell off... :o
Found some stock metal and had them 'match' the paint. Original is darker but I like the new color.
Perhaps there is some connection to that.
Still have to try the latest suggestion by bd though... ;)
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Okay bd, I jumped the flasher terminals and here are the results:
With test light on B- no visible light on either blades.
With parking lights on, bright light on parking blade, dim light on blinker blade
With VOM, parking lights OFF, 0v on parking blade, 1.3v on blinker blade
With VOM, parking lights ON, 12v on parking blade, 7.3v on blinker blade
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Okay bd, I jumped the flasher terminals and here are the results:
With test light on B- no visible light on either blades.
Was the left turn signal energized with the ignition switched ON during this test?
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Affirmative sir
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It sounds like there may be two issues.
First, if zero turn signal power reaches the bulb, then there is an open in the left turn circuit to the bulb. Is there any change in power at the bulb contact when you energize the 4-way flashers with the turn signals cancelled?
Second, voltage measured on the turn signal contact when the park lights are on implies either a less-than-perfect ground to the lamp socket or cross-feeding between the turn and park lamp circuits. Was the park/turn bulb installed when you measured the extraneous voltage on the 'turn signal' contact?
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It sounds like there may be two issues.
First, if zero turn signal power reaches the bulb, then there is an open in the left turn circuit to the bulb. Is there any change in power at the bulb contact when you energize the 4-way flashers with the turn signals cancelled?
Haven't tried that yet, will do.
Second, voltage measured on the turn signal contact when the park lights are on implies either a less-than-perfect ground to the lamp socket or cross-feeding between the turn and park lamp circuits. Was the park/turn bulb installed when you measured the extraneous voltage on the 'turn signal' contact?
No, the bulb was not installed, measured at the blade of the socket.
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Bear with me. Remove the right front park/turn bulb then perform your voltage checks at the left front just as before. Any differences?
And, what were the results with the 4-ways energized and turn signals canceled?
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Sans Bulb, no difference.
Haven't tried the 4-way yet.
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Well, just tried the 4-way, all four corners work, even the front side marker. ???
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It sounds like there may be two issues.
First, if zero turn signal power reaches the bulb, then there is an open in the left turn circuit to the bulb...
Second, voltage measured on the turn signal contact when the park lights are on implies either a less-than-perfect ground to the lamp socket...
You may have a compromised turn signal switch. The front and rear turn signals are isolated through the switch, so there could be a connection problem in the switch that affects only the left front turn and left dash indicator without impacting any of the other lamps. The four-ways are switched separately. Since the four-ways work, the wiring to the left front turn lamps is intact. You can test this by unplugging the turn signal switch at the column and jumping the cab harness plug purple wire to light blue wire with the ignition switched ON. The left front and left dash indicator should blink with the flasher if there is sufficient lamp load with only those lamps.
I still think you have an imperfect ground to the left front park/turn lamp.
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Even weirder- Started working again today... :o
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???
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I had a similar problem but with one of the rear lights, brake lights and 4 ways but no flasher on one side and it was the indicator switch, fitted a replacement and all good again, the left dash indicator light has never worked guess that is the dash pcb at fault?
Graham
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Been awhile, (where is the symbol/icon for music?)
So recently, like the past, the left turn signal began working again, i.e. both front and rear.
To refresh, when it acted up, the left turn signal only lit the rear, the front stayed dormant, and the dash indicator did not light. I could hear the flasher clicking due to the rear brake light being active.
Now, the front and rear are flashing, the dash indicator is working, BUT, the left rear brake light does not work.
I guess, to avoid being pulled over, I can turn on my left turn signal when I brake or slow down...
I kind of suspect an earlier observation by bd that my turn signal device may be compromised.
I can't say if in past cycles of working/not working that I noticed the brake light being operational or not. This go-round I notice it when backed up to a reflective surface at night.
TIA for your help.
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I wonder if spraying electronic contact cleaner would work?
How hard is it to replace the turn signal dealeo?
I think I have one, just wondering how you get the wire terminal through the steering column. Looks painful... :(
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It's actually fairly easy. You'll need a steering wheel puller and lock plate depressor. A tilt column adds a few more steps but no additional tools as long as you don't need to disassemble the tilt mechanism. The T/S switch ribbon cable and connector just slip DOWN through the column. You need to keep the long axis of the connector parallel to the length of the ribbon cable while feeding the new cable down column. If you want to take the easy way, tie a pull-string to the connector before pulling the old switch from the column. The ribbon cable is encased in a semi-rigid flat plastic conduit with a longitudinal slit that slides UP the cable from the connector end once the new cable is in place. It sounds more complicated than it is.
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Thanks bd!
I think I have a replacement somewhere, will confirm.
So in theory, I should be able to plug in the replacement to the connector on the lower column, and verify functionality.
If the symptoms persist, I save my self the trouble.
I was looking at the outboard connectors on the side of the step side to the light fixture, wondering if there were ground issues there, or others.
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So in theory, I should be able to plug in the replacement to the connector on the lower column, and verify functionality.
If the symptoms persist, I save my self the trouble.
Yes. But if the symptoms are intermittent, driving the vehicle that way until you're confident in the outcome might prove unsafe.
I was looking at the outboard connectors on the side of the step side to the light fixture, wondering if there were ground issues there, or others.
Your location description is unclear. Nonetheless, ground issues anywhere can unnerve even the scariest ghosts. BOO! ;D
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I LOL'd picturing driving around with a T/S flopping around the cab...
The location is on either side of the bed, nearest the light fixture. The wiring exits the bed into the light. I believe they are sealed spade connectors.