1982 C10 wiring circuits anyone,,??

[Ilike55s]

Hello to all,, I recently bought a nice one owner 82 C10 Silverado long bed with a 305/auto. The 305 ran great until one day later and the dang cam went flat on 6 lobes! Decided to install a rebuilt 454 and got it running great but am now getting flustered with electrical issues. The PO had given the trk to his 15 year old Son,,who had a love affair with horns and lights and thought nothing bout cutting and splicing wires for the 5 horns and the extra lights wherever he found a 12 volt supply!! I removed all the extra horns and lights but am now having issues with the turn signals, parking lights and instrument cluster lights. I bought (on Ebay) some "BODY & CHASSIS WIRING CIRCUIT PARTS 1, 2, & 3 drawings----for 1982 "P" Series. (I don't understand the "P" designation, tho)
My concern is that the color of the trk wires at the "Inst Cluster Conn" do not match the wire colors indicated in the GM schematic so I'm not sure I can trace back to try and find where he "Modified" same.
I thought the issue might be the circuit board so I bought a new one but that was NOT the answer. I hate to keep throwing dollars at it as I am on fixed income,,,LOL.
Can somebody give me some kind words and good advise,,maybe a good reliable wiring schematic would certainly help!! Many THANKS,,

 

[Frankenchevy]

https://www.gmsquarebody.com/threads/1973-1991-wiring-manuals.14498/

 

[highdesertrange]

P series are step vans. highdesertranger

 

[Snoots]

issues with the turn signals, parking lights and instrument cluster lights.

This sounds like a grounding issue. There should be a multi-pin junction just above the Parking Brake Release attached to the metal kick panel. It usually rusts and doesn't give you a good ground.

Since you've carefully removed the rats nest, I'd start with the ground next and not throw any $$ at it yet.

 

[Ilike55s]

Hey Snoots,,,(LOVE that handle, LOL) Many THANKS for your willingness to help. I was kinda aiming to a ground issue but could not find where the main ground point is and the dang dwg I have does not show me where it might be, but with your clue I am now waiting for the sun to come up so I can go check it out. OH, and I did try to download the link that Frankenchevy posted but could not get my PC to keep the clarity after zooming it for reference,,,??? At this point, I would prolly be more than glad to buy the correct dwg from someone. I have contacted the fellar on Ebay that I got this one from because it is the "P" series and there ARE noticeable wiring differences that I've seen from the vans to the trks.
What's weird is the right turn signal works OK but the left turn signal ALSO causes the cluster dash lights to flash as well if key is on!!! WTH??
Again,,Thanks for the help. ( Ya got a good dwg you wanna sell?)

 

[Ilike55s]

OK, members all,,, Tried to contact the guy that I bought the "alleged" wiring schematic for my C10 but he ain't biting,,,(I HATE that) SO,,I finally took apart the two halves of the fuse box as nothing was making sense when trying to trace out the lighting circuits. I found two of the pins were bent causing a "No Contact" sitiation, got them fixed, cleaned all the other pins and to make positive everything on BOTH sides traced out,,I re-assembled both halves and gave her another try. The friggin lights and gauges on the Instrument Cluster were still working erraticly like before,,,,! Deciding that the one area I had NOT opened was the lights wiring at the rear of trk, I grab my test light and crawl under,,,,There is the biggest friggin mess at the rear bumper you ain't ever seen!! You gotta remember I'm following a 15 year old idiot that thinks he's an electrical engineer,,,I HAVE NO IDEA "WHY",,but he had tied the RT and the LF rear turn signal wires TOGETHER and then tied them both to a 5 prong trailer connection at the bumper,,,!!! WHAT?? WTF??,,,, I cut all that wiring mess off and ran new factory color wires as per the diagram,,SOLDERED and heat taped all connections,,,, and,,AND breathlessly, mind you,,I go and turn the key on and,,,I AM STOKED,,,all the turn signals, parking lights and the Inst Cluster lights work as designed,,,even the emergency lights work,,!!!! I cannot believe all the time I have spent on this one issue alone because of that friggin kid.

OK,,which brings me to my next issue,,,,LOL,,LOL,,LOL. I'm still having issues with the temp and Fuel gauges NOT reading correctly. The temp gauge will go to "O" with key off but will go WAY past hot when key is turned on even with COLD engine,,? I have accumulated 3 different temp gauges and they all do that. They all have those small white porcelene(sp) tabs on the back xcept one that has an additional resister looking thing bolted on. Any suggestions??

The fuel gauge has same issues. From day One, I bought a new switch on the dash as old one was broke. I did not want to mess with replacing the very expensive switching valve, SO, I bypassed the Rt side tank and just run off the Driver side tank. I'm NOT sure if the dang fuel gauge even worked before I bypassed the Rt side tank,,,,?? I also have 3 Fuel gauges and none indicate correct fuel level in tank. They all go to "Empty" with key on. (I KNOW there is half tank of fuel in tank)
Anybody got any ideas,,,??
Sorry for the LONG post,,,,LOL.

 

[Rob Goblin]

I feel your pain on what P.O. does with the wiring. I’m combating that myself although i didn’t have as many horns lol

 

[Scott91370]

I went through this as well but only with the engine bay wires.
Here are a few pictures, maybe they will help.
They're thumbnails but should be able to become full size - if not I'd be happy to email them.

I also have a file listed as Wiring Diagram Complete that is too large (2.5MB) to put here but could email it. Not sure how complete it is but couldn't hurt, unless you already have it.

Driver's side

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Passenger's side

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[Ilike55s]

Hey Rob & Scott,,many Thanks for the replies,, I do appreciate the help. I "HOPE" that I have resolved the issues with the wiring and I now have all the wiring lashed up,,,NOW if I could just figure out the temp and fuel gauges mot working,,,,,,My thoughts on the temp gauge is that the sender MUST be bad as the 3 other gauges I got all go WAY past the "hot" even with a cold engine,,?? What I did is,,I bought a Bosch 3 gauge set with temp, oil press, and volt meter. I hooked the Bosch temp meter TC to cylinder head on left bank and left the factory temp gauge hooked to the factory sender on Rt cylinder head. Do ya'll know how to test the factory sender??
Ya'll got any thoughts on the fuel gauge??
Hey Scott,,I will PM you about the wiring diagram you mention. THANKS Joe r

 

[MikeB]

OK, members all,,, Tried to contact the guy that I bought the "alleged" wiring schematic for my C10 but he ain't biting,,,

Open a complaint against him and ask for your money back. eBay and PayPal almost always side with the buyer.

 

[Ilike55s]

OK,,a bit of an update on my trk. I feel, after finding and repairing the mess at the rear bumper, I can live with the wiring as it stands,,,EXCEPT for the fuel gauge issue. According to the wiring schematic I bought on Ebay, that I have gone ahead and opened a "Case" against the seller as the one he sent me is for the step vans and I have found some differences on the trk that just don't jive. Since the trk ran out of gas because of the bad gauge,,I went ahead dropped the gas tank as I could not see the wiring nor the fuel hoses to make sure the PO had not messed with those.
NOW,,according to the dwg I have, the one wire from the fuel level sender is suppossed to be "PINK" but what is there is a RED with white stripe wire,,,??? I opened the loom and there is NOT a pink wire in the harness,,,WTH,,?? I removed the whole assy and rehooked the red/white wire and the ground and the dash gauge goes to overfull as soon as key is on AND stays there even with key off. I manually move the float up and down and no change on the dash gauge. What Now????
Tomorrow at first light I'm gonna check the harness all the way to bulkhead and see if there is a PINK wire at fuse box,,,,. CHIT,,,CHIT,,,I'm gettin so tired of tracing wires
ONE OTHER THING,,if I may,,, on the tank, there are three metal lines,,3/8" for fuel to fuel pump,,,1/4" for the return line to tank,,,BUT what is the small 3'16" line for??????? Fuel Pump at engine only has two metal lines,,,???
Any and aLL HELP WILL GREATLY BE APPRICIATED!!!!

 

[Scott91370]

If I remember correctly the smallest line (3/16") goes to the charcoal canister by the driver's headlights.

As for the red/white or pink wire, my diagrams all show PINK in spot 30 on the bulkhead going through the firewall. Pretty sure it is in the same loom as the taillight harness.

I feel your frustration. When I got mine the previous owner had someone do all the work and I went through so much tracing wires and colors it drove me mad. It can be especially difficult on older vehicles because the colors fade and purple looks like pink or pink looks like white - dark green looks like light green. There was a whole lot of going on.

I've got a bunch of diagrams and would be happy to email them - I know a lot of people here would too.

 

[Ilike55s]

Hey Scott,, I did get those dwgs you emailed ,,just haven't figured how to print em from the PC, so I been scrolling up and down and cross ways,,,,LOL. My printer doesn't seem to want to print in soooo,,,, I WAS gonna open the harness at the fuel tank area,, but it has turned COLD here and windy and my work area is open on the east and south sides so it too danged cold to work out there today but the wire that was hooked to the sender unit "IS" red/white stripe,,? Maybe it is pink at the right side fuel tank sender unit,,,? I had to order a new sender unit as this one was off and on when i was checking the operation out of the tank,,,maybe why the dash gauge would go to OVERFULL when key was on,,??
On another note I was thinking about installing a "Manual" switching valve, like we used to do back in the olden days,,,? I've got two of those all brass 3 way valves,,if I can remember how we used to address the return lines,,,???

 

[DanMcG]

this might help ya with the fuel gauge issue.
http://www.fifthaveinternetgarage.com/tech_tips_gas_gauge.php

 

[Ilike55s]

Hey DanMcG,, Many THANKS for that link,,I opened it and dang if I didn't just do a whole lot of reading and making copies,,,LOL. That right there is one great site, so I put it on my Favorites!!

Again,,THANKS,,!!