Need some electrical help please

[hdff]

Tonite I was looking for the wire that goes to the dome light , think I found what I was looking for. Backed the truck out to get something out of the garage then went out to pull the truck back in. When I turned the key off i noticed light on the external gauges did not turn off as usual. Did some checking and the whole fuse box appears to be hot. I don't have a radio or anything else to see anything is on. I just got this truck about a month ago and am still trying to figure it out. Turning the key off will kill the truck but no other power apparently. Undisclosed to me prior to me buyin it the wire harness has been whored up a little . I unhooked the battery to kill the power but why won't the key kill the power. The gauges are hooked up to a switched slide on the fuse block. The truck is a 1971 Cheyenne super. Thanks in advance.

[magicoolbus]

Courtesy light wires are orange and white. The they should go down the A pillar. The orange is the 12volt battery source and the white is the ground. When you rotate the headlight switch CCW, you should feel a click and that's what grounds the light. If you have door switches, they will ground the system individually when the doors open. Lots of write ups on this topic in the electrical system, use the search function. Spell carefully, it only lets you do one a minute. Crummy feature, but really the only complaint I have about the site.

[hdff]

Originally Posted by magicoolbus

Courtesy light wires are orange and white. The they should go down the A pillar. The orange is the 12volt battery source and the white is the ground. When you rotate the headlight switch CCW, you should feel a click and that's what grounds the light. If you have door switches, they will ground the system individually when the doors open. Lots of write ups on this topic in the electrical system, use the search function. Spell carefully, it only lets you do one a minute. Crummy feature, but really the only complaint I have about the site.

I think I found the dome lite issue and hopefully the wire that goes to the door switches,it got dark so I will finish that tomorrow, my big problem now is why the key will not kill the power to the fuse block. Could the ignition switch have gone bad during the 2 starts I did tonite? I' m not an electrical expert by any means but doesn't the fuse block get it's power thru the ignition switch?

[Wrenchbender Ret]

Some of the fuses go through the ign. switch & some are hot all the time like stop & dome lights.

[Big Kev-O]

By "external" gauges you mean the PO added afternarket gauges? If so he did not wire the feed for the gauge lights correctly. There is a specific wire that comes out of your headlight switch to power the factory gauge lights that should have been used(spliced) to power your external gauge lights so they dim when the knob is turned. I believe the correct wire is the Grey wire running from the headlight switch to the instrument cluster plug.

I'm at work now but I will verify the proper wire when I get home. These trucks really are simple.

[hdff]

yes they are aftermarket under the dash guages. the PO said he didn't trust the accuracy of the stock guages in the new dash he put in. are the stock guages that unreliable? it is a stock 402.i remember seeing a plug on the fusebox that said inst panel with a cut gray wire on it and i also seem to remember seeing a loose gray wire, i will investigate when i get home from work. the dash lights dim i think but the AM guages don't. i will try to see where the panel lights are getting their power from. the AM guages are getting their power from what appears to be an extra switched plug in the center of the fuse block. there is one of those spade connectors that makes 1 to 2 male spades. 1 wire splits to 3 and goes to each guage for the light and the other wire piggy backs to the guages to power themwith the key off the lights are on and the guages are still powered up. unplug them and the lights go off and the guages go to their unpowered position (0). everything worked fine till last night when i moved the truck out of the garage and then back in later. after using the ignition twice is when the problem started making me think something in the ing switch might have broke. i will try to take a pic of my mess tonite and post it up. it just kills me when people cut wires and don't know what their doing!!!!!

thanks for your replies, with ya'lls help i will get thru this and get to enjoy my truck..............

[POPO1984]

I think he probably wired the gauges power into a constant circuit is it possible that you just never noticed that the gauges stayed lite before. I guess the switch could have gone bad. I might have an extra switch in my pile of parts you wanna try it. Im off of Spencer Hwy in South Houston.

[hdff]

Originally Posted by POPO1984

I think he probably wired the gauges power into a constant circuit is it possible that you just never noticed that the gauges stayed lite before. I guess the switch could have gone bad. I might have an extra switch in my pile of parts you wanna try it. Im off of Spencer Hwy in South Houston.

oh no they were definately on or off, they are white faced with led bulbs. the white is not really my cup o tea but i have only had it a month and haven't had time to deal (change) with it. i might take you up on that trying the switch. i will get back with you, i am working days till wed and have busy evenings getting ready to go on vacation thursday. i will be back in 2 weeks. i am at burke and fairmont so we are close thanks

[POPO1984]

No problem. Ill look in my old parts for one tomorrow. I'm pretty sure I had another on in there.

[hdff]

got home and checked some wires, dome light wire had come loose. hooked up the battery and the electrical problem with the gauges was gone. hummm... here is what I got. also where do the door switch wires hook up at?. I am pointing to the wires that the gauges are hooked up to, the wire to the dome light and some unknown wires. also where does the cab bed light get it's power from? also pictured is the gray wire talked about above that I think is my instrument wire that is cut. the dash lights do dim with the headlight switch but the AM gauges do not. what a mess!!! thanks

[LSUMurse]

This thread might help. It's got wiring diagrams for our trucks.

http://67-72chevytrucks.com/vboard/s...d.php?t=185856

If you're like me, you're eyes will start to go crossed when reading it.

[Big Kev-O]

WOW ugly, but still much better than how I received my truck, burnt spaghetti. I got so sick of electrical probems I rewired the entire truck with a EZ kit.
The grey wire that should power your gauge lights comes out of your headlight switch and goes into the instrument cluster. I attached a picture of the headlight switch plug that shows the terminal for the dash panel lights. It is the only terminal that dims when the headlight switch is turned. If you unplug the switch it should be easy to find. Your gauge lights should be powered by that circuit.

Do your dash lights dim when the knob is turned? They should.

[hdff]

update.
today i decided to drive the truck to work since the electrical issue seemed to be resolved last nite. drove about 10 miles to a taqueria to get some breakfast tacos for work and when i turned off the truck the guages stayed on. so when i got to work i disconnected the battery. i am curious to see it they are on or off when i hook the battery back up



Big Kev-O was the ez kit hard to install? i assume that you installed it. also where do you think that cut gray wire off of the clstr spade is for (see above picture). i cannot look at the wire diagram here at work due to it being blocked

[Big Kev-O]

The EZ kit was fairly simple. If you understand how a 12v DC circuit works then you can do it. The kit I purchased was the EZ wiring universal 21 circuit kit from ebay for less than $200 shipped. The process is time consuming but simple. I used split loom to shield the wires but only because I could not find any of that expandable wire loom locally. The expanded loom would have looked much more pro than split loom. I soldered and shrink wrapped all the important connections. It was the second kit I have installed. If you decide to go for it and run into questions I'm here to help.

Things I learned:
-If you don't solder everything use non insulated butt connectors and heat shrink instead of insulated connectors. It's much cleaner and the heat shrink seals the connection.
- Don't forget to wire the neutral safety switch. The purple wire that goes from the ignition switch to the starter must run thru the NSS.
- Take pictures of everything before you unplug it. might need to reference later.
-If you but GM 56 series terminals and a crimp tool you can shorten wires and reuse your factory connector plugs without ugly butt connections. I like my work to be as clean as possible. Wish I would have waited for the terminals and crimper. About $25 for everything on ebay.
- Before you shorten any wire inside the truck make sure it reaches where you need it to go outside the truck.

Can't remember if my truck had that grey wire plugged in but it looks factory. Trashed my old fuse block so can't help with that.