The Stovebolt Site Forums The Shop Area The Electrical Bay New harness questions!

With out getting long winded about this it'll be better if I tell you what I got and what I want to do. When I started to restore my 1951 GMC 3/4 ton long bed 3 years ago, the wiring harnless was in such bad shape I decided to just cut the whole thing out during disassembly. To give you an idea of how bad it was I had a combination of stereo speaker wires and short sections of battery cables being used as dash wires. There was nothing good and nothing worked. Over the last 3 years I have collected parts and now I'm ready to do the electrical, the one aspect of this project that I've been avoiding like the plague. I hope my questions don't insult anyone's intelligance. I have a 1962 Chevy 235 and from what I can see someone had converted it to 12 volt, but now that I'm starting from scratch I'm having a hard time understanding the best way to do it with what I have. I want negative ground, 12 volt with turn signals, 4 ways, a mordern stereo, electric wipers, fog lights, and a cigarette lighter. I have a: Chevy duty wiring harness, looks good, is numbered, and looks as it should be easy, however the directions are 2 pages and im already lost in their numbering system. It goes from 1 to 42 and either I'm not understanding something or these wires are missing 4,5,6,7,9,11,17,21,25,27,28,29,30,31,36,38,39,40,and 41. I have figured out that wires 31-35 are for the turn signal switch. I have a signal-stat 900 which is a 7 wire and i only have 5 wires for the switch in the harness. I've read some of the threads on 12 volt conversions but they seem to be more centered around original systems and adding turn signals to original trucks. This is what I have, an 80 amp internally regulated alternator from Patricks. I think that the harness is wired with the DA plug. A 12v internally regulated coil, a newport engineering 12v wiper motor, a new 12v heater fan motor and a reostat type fan switch, a 12v cigar lighter, 12v 5" fog lamps and a 12v new headlamp switch with the fuse between the stop and dome terminals. I forgot to mention that I think I have a 6v starter which from what I've read will be OK to use but rather than a floor start I have a push button off the original ignition switch. I just realized that I'm getting long winded, so I will leave it here for now. Sorry I know this is a lot for one thread and I should be more specific,but I was hopeing before I got going on this one of you guys that have worked with a harness and parts like mine could give me some advice.Thanks

Read your directions twice then keep them with you while you are running wires,for quick info.I did'nt have as many wires but still had a time with it.Be calm and stop,when you start to get frustrated,(this is suppose to be fun).The numbering system and color coding should go together at both ends.It can take awhile to put everything together and you will feel great to be able to say I did it my self.Good luck jimmy1

Jeff

like Jef sez, stay calm if it's a factory style harness, it helps to lay out the works in the patterns that it lays in the truck, reduces the amount of confusion, like you only have to deal with the ones under the dash, or the ones under the hood, etc - length of the cables says a lot .... what you think are missing number on a diagram [probably meant for a number of different applications] will be there some place depending on what those numbers call for, some may be ones not included in your particular harness, pay attention to color .... it helps to have the factory diagram as a reference, it should have the color code on it, which is all you really need

for the accessories you're best off to have a fuse panel that they're fed from, and of course a factory 51 harness won't include any wires for optional accessories, especially electric wipers and fogs .... otherwise there'll be no difference in the original diagram from 6-12V

and check in the tech tips, there's one for the sig-stat wiring

Bill

when i changed my wiring harness i made three copies of the wiring schematic. when i got the harness which had numbered ends and a sheet with a generic description of where they went. i laid out the harness the way it goes in the truck and started tracing the harness with the schematic. when i made sense of a particular circuit i used masking tape to mark the wires at both end as to where they originated and where they terminated with the word not a number. as you finish tracing the circuit then mark that circuit on the drawing with a yellow high lighter. when your done tracing, all the lines on the print should be yellow and all the wires labeled. since you ripped out all the wiring you wont need a print to follow that as you tear it out.

when you start putting in the harness as you complete a circuit take a drawing and hi lite that circuit and track your progress as you go. when all the wires on the print are yellow you should'nt have any loose wires on the harness. hook up all your assesories after the harness checks out. something that should make it easier or less confusing is dont worry about headlight harness that goes from fender to fender and its cut and dry. its all the stuff under the dash that looks hard but it isnt once you have the harness labeled to the point where you understand it.

I don't know if this Chevy duty harness is a direct repacement for the original,but it must be close.I have the GMC service manual and the locations are spot on.But I always get triped up by the simple stuff.This isn't a cloth coverd harness like the one in the truck.It has modern wires and all the ends are on.Nice for a repo! I started to color code the number and color of the wire with the number on the directions with colored pencils.It's helping.I don't know much more about the harness other than it was bought from Patricks and the guy never used it,so I took the chance and bought it.The directions say it's for a 1950-52 wiring harness W/Alternator copyright1987 Chevy Duty Inc. Thanks

I wouldn't try to wire any of the accessories into that harness. I'd suggest you first concentrate on getting that harness installed. Then build a second harness with a fuse block for the accessories with it's own feed from the starter terminal.

A 1962 engine is a 12V engine. Your 6V starter will not mesh with a 12V flywheel.

It must be a 12v because it ran.On the instruction sheet for the starter it shows three hookups 6v foot start,12v foot start and key start.the first two simple drawings show a starter with a square solenoid the last one which looks the most like mine is round.Thanks