Color Wiring Diagram FINISHED

[JT's 70c10]

Anyone have any info on "Shaved side markers)? On my truck (70 C10 fleetside)im having an issue with the break, reverse, and "night" lights. all new wiring from the cab back, including new harness for the lights. Is it a ground prob? or do i need to change out the light switch (All the front lights woork great )? and the rear side markers are not hooked up at all.

[L8brake731]

Awesome! Thanks for the good work!

[TurboGuy]

just wanted to say thank you

[tnoftsger]

First, a BIG THANKS to all who worked on the wiring schematics, there great. I do have a question tho, i am attemping to un-hack the wiring on my '69. Charging system is not charging due to lack of a 12v on terminal 4 of the voltage regulator. This brown wire is intact to the bulkhead connector. Now, i have instrument cluster, not lights. I have found the brown w/white stripe wire loose in the dash. But is the other wire connected to this terminal at the bulkhead connector that goes to the instrument cluster is a black w/brown stripe from the bulkhead? Do i have that right?

[JT's 70c10]

tnoftsgr,
Check that it has the ground to the body (Pass side just behind the cab under the truck) If thats intact you will have to trace every wire back to the cluster. The ground will also cure a lot of other probs too. And just a hint, dont just look to see if its there. You must remove it, sand down the frame and body (add soome wd40 befor you put it back togather). Also its not a bad idea to run a second ground from the batt, to the wheel well (pass side). That could clear up the charging prob too, worth the 15 mins to do it.

[WORP67]

Thanks for all the work that was put into these. They will help me alot.

[tnoftsger]

Ground is good, a welcome suggestion tho. I guess what i need to know about the wiring schematic is, with gauges, did the brown wire from the voltage regulator turn into a black w/brown stripe and a brown w/white stripe on the cab side of the bulk head connector.

I have continuity between the voltage regulator and the brown w/white stripe cab side, but not between the voltage regulator and the black w/brown strip in the gauge connection.

[JT's 70c10]

Looking at the diagram again, its very hard to tell what the right wire it is. Ill look at my 70 this weekend and check it out for ya. But i fear that your's just might have been wired/ rewired wrong. Ill post somthing for ya this weekend for ya.

[tnoftsger]

I appreciate the help! The black w/white stripe is good from the bulk head to the instrument cluster, but not connected to the brown wire on the engine side (the one that goes to the voltage regulator).

Could be that i'm mis-interpreting the diagrams, I assume that the wire leaving the instrument connection labeled "Alternator", the black w/white strip wire connects to the brown wire on the engine side of the bulk head connector. Maybe by "Alternator", it mean the post on the back of the Alternator???

[72shymedblue]

Thank you for these diagrams. I have owned my truck (72 Cheyenne medium Blue) for 2 years now, and of necessity have just now started trying to sort out the jumble of non-standard wiring that it has accumulated over the past 40 years. Many extra wires and bad connections both under the hood, and under the dash. It's a mess. My immediate problem is as follows; There was a (non-working) add-on cruise control that I removed. After removing the wires to it, (and apparently one extra, maybe more) it would not start, but cranked fine. So i figured that i had removed a wire between the ignition switch and the coil. Right ? So I connected a wire from the ignition to the fusebox, and it started and ran fine. But only for a couple of weeks. Then my battery ran down. A friend told me that wiring it this way meant that the coil was powered even when the key was off. So I disconnected the wire from the ignition (orange or red) and now I am trying to find how to connect the ignition to the coil (if that is what I need to do.)
You have helped me immensely.

[firemanmario]

Just wanted to say thanks for the work you put into these. I'm about to get started on my wiring and these will help tremendously

[71blazervt]

71 blazer. I have an additional wire harness under the hood. It has 3 wires going the the carb and one going to the trans for back up and another green? all are coming off relay's on the fire wall. trying to find out. Does any one have this diagram?

[jhaymon]

for those asking, the 18t wire is normally for a fuel sender.

[extremesounds13]

Anyone have anything that would show wiring for rear A/C on a 72 GMC burb. Mainly just need to know where the orange wire gets its power from, mine doesn't have power.

[mikewayne]

Hey thanks for such a good informative link as this has made it easy to understand the wiring patterns of these vehicles, as these electronics make a really important part of any vehicle and are the ones that are most tough to understand.

[BrutonLS1]

Whats going on with these wires??? The picture is too distorted for me to tell

[BrutonLS1]

I wish I could have made this bigger so y'all could see the issue i'm having, you may have to reference to another diagram on this thread. I just can't tell which holes they're going into and why there aren't as many wires on the other side.

[magwakeenercew2jh]

Originally Posted by BrutonLS1

I wish I could have made this bigger so y'all could see the issue i'm having, you may have to reference
to another diagram on this thread. I just can't tell which holes they're going into and why there aren't as many wires on the other side.

Hey, BrutonLS1.

Here's a bigger diagram. If the Forum's jpeg format works. You can save in and make it larger without it "fuzzing up".
I'll likely tell/ask you what you already know.

The wires plugging into the fuse block are not matched one for one coming thru. There are elements in circuits that are "jumped"
together to be handled by a common fuse at the fuse block "train station".

I can't tell what specific wires you are asking about. But, since I've poured over every wire waaay too many times,
if you just hint at what your issue might be, I bet a bunch of folks will chime in.

I spent a while focusing on your diagram "circles". Then, I realized that you need to front some more info....I'll try to enlarge the specific areas you "highlight" in a minute and post them.

[magwakeenercew2jh]

Oops! Your elect. areas......

[CST10]

Hello All,

I have a 1970 cst10 that I seem to be having electrical issues in the dash cluster. Also missing lic plate and reverse lights.

Can some one please send me the full diagram so I can print to help try and solve this issue.

Thanks.
thedagobergs@eatel.net
Posted via Mobile Device
Posted via Mobile Device

[truckster]

I realize this is an old thread, but I've used the information a number of times for myself and to help others.

Thanks!

[MarineChevyDriver]

Can anyone explain what it means to have a 12, 18, or 21 circuit harness?

[harley rider]

this is the amount of accesories you can power. if you have no things like electric fuel pumps or fans or ac, ele. windows or seats, you can get by with a 12 circuit. there are some 9 circuit kits from rebel or E-Z wire I prefer the E-Z kit but there about the same. the more stuff you have the more circuits you need .

[MarineChevyDriver]

Originally Posted by harley rider

this is the amount of accesories you can power. if you have no things like electric fuel pumps or fans or ac, ele. windows or seats, you can get by with a 12 circuit. there are some 9 circuit kits from rebel or E-Z wire I prefer the E-Z kit but there about the same. the more stuff you have the more circuits you need .

That's the best explanation I could have asked for. What is the most common? I see a lot of 18's out there on the forums.

[crakarjax]

I went with 21 just to be future-proof. You don't have to use any circuits that you don't need.