84 c10 owned since new is over charging

[skinu]

I got a problem that after 4 new 10si alternators and 5 or 6 good used ones I can't get it to stop over charging. I've tried and done everything told to me from rewiring the sensing wires to batt change new fusiable links at starter now engine bay. I have replaced the ground wires and cables. it starts and runs great but gauges,volt meters and other methods show 17 to 18 volts now I lost my head lights and still show no shorts in any key position. I'm stumped and lost ,C'mon guys someone must have the answer I need my baby back...

[1967KaiserM715]

How old is the battery?

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[VileZambonie]

How have you verified the charging system output? Are you simply going by your gauge readings? you need to measure voltage output with a meter as well.

Losing your headlights is a separate issue. Start at the bulbs and check with a test light in high and low B+ then check the ground circuit.

[1967KaiserM715]

How have you verified the charging system output? Are you simply going by your gauge readings? you need to measure voltage output with a meter as well.

Losing your headlights is a separate issue. Start at the bulbs and check with a test light in high and low B+ then check the ground circuit.

He said gauge, volt meter, and other methods, so it sounds like he has done some proper diagnosis.


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[skinu]

Yep guys I have double and triple checked with volt meters and the battery is new and even used the year old out if my 76 k10. The lights are a separate issue i'm hearing but this started when the over charging started. Today I rewired the three alt wires then one of the new alternators napa tested was installedand it ran at start up at 11.7 volts, all my readinds are with volt and multi meters, the dash gauges are auto meter from 08, ultra lite II'S and read same as external test meters. Today's my birthday and hoped to go cruising. Whats going on...I said that I owned the truck since new actually my grandfather did and upon hid passing in 95 I was given it but know it was never abused and always serviced. It also has a new ignition switch and ran a new sensing with so I just don't know, besides removing batt cable and putting test light between post and cable is there another way to check for shorts, Thanks for the input.

[1967KaiserM715]

How many grounds in the engine bay?

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[bd]

It sounds like the regulator has lost its battery reference.  Can you post a pic of the wiring that clearly shows how it connects to the regulator?  Using a test light probe the #1 and #2 regulator terminals with the harness connected to the alternator and the ignition switched OFF and then ON and describe the results.  Is there any voltage indication when you connect a voltmeter between the alternator case and battery negative post with the engine running?  How about if you measure between the regulator #2 terminal and the battery positive post?

[skinu]

I ran all the checks and tests you guys said and these are my results ,the tests were done twice with a new and diiferant batt and alts. no volts between the alt case and the batt ground. got 1.7 to 3.8 volts on one side of plug and 11.3 to 17.0 on the other and up to 18 volts at the stud. I'm lost as is everyone I ask.

[bd]

I ran all the checks and tests you guys said and these are my results ,the tests were done twice with a new and differant batt and alts. no volts between the alt case and the batt ground....

This is good.  There are no issues in the charging system ground connection.

...got 1.7 to 3.8 volts on one side of plug and 11.3 to 17.0 on the other and up to 18 volts at the stud....

Elaborate.  Why a range of voltage measurements: 1.7 to 3.8 on one side, 11.5 to 17.0 on the other?  Different alternators?  Where were the meter leads connected during these measurements?  Was the engine running?  You measured 18 volts at the output stud, relative to what... stud to ground, stud to B+?  Voltage measurements are meaningless if the connection points aren't clearly stated.

Where's the requested pic?

[skinu]

I cant load a pic , will have help on that in the p.m. All tests at stud and plug with volt meter + and engine running.same with all known good batts and alts. while holding volt leads is where they range in readings ,ground my tests at the batt ground post/clamp. smell no hot wires or burning and ran new ''sensing''wire and soldered in new plug for alt. ,new cables,ground straps, and test with three known good batts. and got 7 know alts two are new napa and autozone and others test 14.7 running volts on running trucks/cars barrowed off of. No one online or in stores can figure this out and I've ran every test suggested. also ran continuity wire tests from starter and alt as wellas any other places thought might need. also firewall studs junctions seem good . where does sensing ''y'' off or does it.also some call the plug #1 and #2 and others vice versa ,what is correct I see the cast in 1 and 2, but some schematics are reversed. So I'm clear the lighting is is separate after it leaves starter? Thanks I'm so fried over this. also once before all this started I seemed to get shocked while driving but showing no shorts ,that was while arm was on door with window open but never done it to passegers or any where else.

[bd]

Don't let the truck make you frantic.  I'll try to help you, but I need you to focus on our conversation and disregard everything that you've heard from previous sources that led nowhere.  Ignore what you've been told - it's irrelevant.  Fixing your attention on false data provided by local experts will just prolong your confusion.  If you do exactly as instructed, perhaps the confusion will straighten out and you'll resolve the problem.  No guarantee, but it maybe your best opportunity.  When I ask a specific question, provide your answer to that specific question.  Don't substitute something else.  If you aren't tracking with my question or instructions, stop and say so.  If you become overwhelmed or too frustrated, take a walk and focus your attention outward until your space settles down.  Agreed?


I'll address one problem at a time until it's resolved, then move on to the next.  Fact: overcharging is a regulator circuit issue.  To diagnose the overcharging complaint, you need to determine if and where voltage losses occur in the circuit.  To do that you must perform voltage drop tests.  Voltage drop measurements are made point-to-point on a circuit that is operating.  The voltage measurement acquired with the positive probe is always relative to the circuit placement of the negative probe.  So, for a voltage measurement to be useful, it is necessary to know where both meter leads are connected to the circuit.  Any measured voltage drop then exists between those two points.  Does that make sense?

...All tests at stud and plug with volt meter + and engine running...

Where was the meter negative lead connected during the above measurements? 

...while holding volt leads is where they range in readings...

So the voltage variation occurred because the probes were moving around while you were holding them?  You need to steady the probes for precision (repeatable) measurements.

...some call the plug #1 and #2 and others vice versa ,what is correct I see the cast in 1 and 2, but some schematics are reversed....

Use the numbers cast into the alternator case.  Looking from the front of the vehicle, the #2 regulator pin should be on the left.

Now, based on the description of voltage drop tests, above, I'll ask again.  With the engine not running and the harness connected to the alternator, use a test light to probe the #1 and #2 regulator terminals with the ignition switched OFF and then ON and describe the results.  Start the engine and probe the #1 regulator terminal.  Describe the result.  What is the voltage indication when you connect a voltmeter between the regulator #2 terminal and the battery positive post?  To post the pic you may need to resize it or use a lower resolution on your camera.

...So I'm clear the lighting is is separate after it leaves starter? Thanks I'm so fried over this. also once before all this started I seemed to get shocked while driving but showing no shorts ,that was while arm was on door with window open but never done it to passengers or any where else.

Stay focused!  Forget about the headlamps until you have the charging system resolved.  Receiving a shock off of the door is a result of a floating cabin ground - to be addressed later. 

[skinu]

I got it BD,thanx for the advice it really was making me stressed. THANKS to all the guys who offered advice! Now for the weird part ,there is about 4'' of wire between the fusable link and the starter lug ,mine has one eyelet with two wires coming out. This section has rubbed the coating off and had only one or two strands and must have been grounding out on the metal tube it sits in, I was told to check this by a 86 year old guy who stops by and talks trucks I did but found nothing three or so times he then said it seems to him that the little 4'' wire piece would lose continuity ,so I cut it just before the link put on a new eyelet and wire section wrapped it up and sure enough I cut open the wire and it don't seem to be copper its bright silver ,fine and very flexiable and has little or no continuity using a volt meter. All voltmeters and gauges show 14.7 engine running volts and no shorts. I took him out for ice cream and he said when he had a little garage in his day he seen this more than a few times with early 80's vehicles. He's now showing me how to build a turbo 350 with a 700r4 first gear for my 4x4 and turning down the drums on a little lathe to get more cluthes and steels in. THANKS AGAIN GUYS I was about to trade my bow tie for a neck tie and step off the milk crate.

[bd]

Congratulations on finding the problem...but...you're not quite done....

The two 4" wires that you removed were fusible links.  The bulges in the two wires were just splices connecting the links into the chassis wiring.  By cutting out those two 4" wires you have eliminated the primary circuit protection for the vehicle, exposing it to catastrophic electrical fire!  Replace each link with a 6" length of 14-ga link to protect the larger 10-ga wire and a 16-ga link to protect the smaller 12-ga wires; see How to make a Fusible Link.  One of the 12-ga wires protected by the 16-ga link connects to the #2 regulator terminal.  That faulty link effectively isolated the regulator from the battery resulting in severe overcharge.  That same link supplies power to the headlamps. 

Once you replace the fusible links, primary electrical and fire safety protection will be restored to the vehicle.  It's important that you reinstall the links!

[skinu]

Thanks bd I should have been a little more clear. I did not remove the fusable links I cut off the 4'' of wire between that and the starter lug. can you tell me where the two links at the starter run to. also what type of solder do I

[bd]

I should have been a little more clear. I did not remove the fusable links I cut off the 4'' of wire between that and the starter lug. can you tell me where the two links at the starter run to. also what type of solder do I

The 4" of wire that you cut off WERE the fusible links.  Unless the factory wiring had been altered by someone before you worked on it, what you are calling the fusible links are just factory molded splices that attach the links to the harness.  If you disagree, clarify by posting a pic of the wires connecting to the starter. 

In addition to the battery cable, there are two fusible links that attach to the 3/8" battery cable stud on the starter solenoid - one 14-gauge link and one 16-gauge link.  The 14-gauge link splices to a single 10-gauge red wire that runs to the firewall junction block located above the back of the engine.  The 16-gauge link splices to two 12-gauge red wires - one of the 12-gauge wires runs directly to the alternator #2 regulator terminal, the other runs through the firewall bulkhead connector into the cab to feed the headlamps, tail lamps and interior lamps.  So, THREE factory harness wires connect to the starter through TWO fusible links. 

Industry-wide standards call for fusible links to be 6" long.  Fusible wire is specially made to function as a fuse.  Do not substitute any other type of wire.  Use 60/40 or 70/30 rosin core solder.  The ratio is the amount of tin to lead.  Firmly crimp the terminals before soldering.  Specifically, use adhesive lined, dual wall, polyolefin heat shrink tubing to seal the splices after soldering - 3/16" and 1/4" are the sizes most frequently needed, available from Harbor Freight, Del City, et al.  The heat shrink tubing sold by most automotive parts houses is expensive, unlined, single wall tubing.  Avoid it.