Finally got my 94 1500. Didn't pay too much, got it for what it's worth. I have a few electrical issues I want to get sorted out.

Tail lights: They don't get bright when you step on the pedal, glow dim when you turn the headlight switch on, the nighttime running basically. Just don't get brighter as you step on the pedal.

Power locks: don't work. Maybe a fuse? What else to check other than a fuse?

Turn Signals/ Hazards: turn signals work, but hazards don't. When you turn the hazards on, nothing happens, and then when they are on you lose turn signals too. The switch likes to stay in the on position and won't click back to the off position, so you have to fiddle with it. What's the possibility of it being the switch???

Headlights: brights work, but sometimes low beams don't. I think it's the brights switch in the colum' b/c when you turn the brights on, the low beams go out, and when I turned them off, the lows are supposed to come on. I fiddled with the brights switch and got the low beams back, and the switch seems to be working as normal, but I don't want to get stuck with just brights driving for over an hour at night again.

Radio: this one doesn't make sense to me. The radio doesn't work, no clock no display, buttons do nothing, neither does volume control/switch. But when you turn the lights on the backlighting for the buttons in the radio comes on. So I'd assume it's getting power, but I'm sure.

Radio and tailights are my biggest concern right now. I'll start some of my own dioagnaostics, as much as I can do, but i don't know these trucks like y'all.
Runs and drives great tho.

I went to drive the truck about 2 or 3 months ago, and the radio worked, but still no tail lights or hazards. Then it sat for that time, finally picked it up again today and no radio, and all the problems above still the same. And for you guys to know to help, this sat at the farm for all that time, so what's the possibility that mice chewed some wires is high, so that's going to be my first priority for checking on the tailights. If y'all could help identify my other problems, that would be awesome. Thanks

 

I plan on checking the IOD fuse tomorrow after I get home from school and work. I'll let you know what I find.

 

The first thing you can do (and the easiest) is to check fuses and relays. Next would probably be switch connections (will require more 'digging') and after that point if theres no luck I'd assume you'd be best off tracing back wires and ensuring theyre all properly connected to where they are supposed to be, not shorting, and not chewed/exposed.

Speaking from experience, electrical problems are THE WORST problems to have to self diagnose and fix in a vehicle, as they're often hard to get to, small, and sometimes slip by undetected even after you think you've eliminated an area from fault. Best case is often splicing in a new section of wire and heat shrinking to make it look/function as factory, worst case is running a new wire the full length. Anyways, my advise is to just go down the troubleshooting list and test things from easiest to most difficult and hope its the former.

 

I'll check all the fuses, and how do I test the relays? Do any of the things I have not working power off of relays?
But for now, my main concern is brake lights. I'd prefer not to get in an accident or anything near that. What fuse would the brake lights run off of? Could the switch on the pedal ever fail?

 

If you have a trailer harness, check where that harness hits the main rear harness. Those are notorious for causing issues. Also check all grounds for the rear lights.

Of course, the brake lights also go thru the multi-function switch.... (turn signals, headlight dimmer, hazards, are all wired thru it.)

If you don't have one already, grab a service manual for your truck from this thread. Wiring diagrams are in section 8W.

 

I don't have a trailer harness, at least I don't think. So instead of spending hours on testing and tracing all the wires, so I thought I'd just buy a new multifunction switch and see where that gets me. I assumed since my blinkers are working, that the wires that trace back to the lights are fine, and I knew my pedal switch was fine as my cab light would work. I threw a new multifunction swicth in and boom. All the lights work!

Now I have to trade down the radio problems. I was reading while collecting info, and came across a thread on another site that takes about similar issues, but with a Jeep. It talked about how his battery caused his issues. A bad battery, even though it seemed fine as it would start the truck, cause the radio to not function properly. He replace de the battery and everything worked great. It also stated to try to reset everything by undoing the battery for a couple minutes, and I tried that. Here's where It gets interesting.

So I disconnected the battery, and Once I reconnected the battery, the little orange LEDs came on that illuminate the bass/treble etc, Slides. And I also, when turning ignition from on and off, could hear the speakers turning on and off. Sounded like a guitar amp, or a big sound system speaker when it turned off. But I still have no display/clock or any sound or function out of the radio.

Funny thing is, when I drove it to school today and yesterday, those little lights and those sounds were there. But when I went to take it to work today, when I started the truck, those little lights and the sounds didn't happen. And suddenly it's such a coincidence that they turn on again when I mess with the battery.

I'm going to have my battery test at my local auto parts store and see if it's bad, even though it seems ok. But other than trying this, I'm stumped. If the battery is not the problem, I'm going to trace the power and grounds, see if they are good. But what else could I try, maybe a little easier before tracing the powers and grounds? Is this a common problem?

Btw I have the infinity sound system

Thanks

 

Do you still have the stock head unit?

Do your dome lights work?

 

yes i still have the stock unit, and yes my dome lights work. The IOD fuse looks fine. i Just don't understand how those stupid little orange LEDs can work, and i get those on and off noises from the speakers, but i don't have any power on the radio screen or any display. All fuses look good. Battery tested bad, so i replaced it, didn't help the radio issue, but sure starts a little easier now.

 

I went to use the 94 service manual, and it doesn't work. The 95 goes to google drive but the 94 goes to some Microsoft one drive thing. if there would be any way to get the 94 manual back working, please do. For now ill try to use the 95.

 

Looks like the Radio gets power from a couple different sources......

Fuse 1 in the PDC, (under the hood) That feller is 50 amps...... and supplies fuse 17 in the fuse block on the side of the dash. (which then runs to the radio.)

Fuse 3 goes to the ignition switch..... and then via fuse 7, to the radio. There's at least one more, (fuse 13) that supplies power for the illumination on the radio.