Electrical gremlins strike again!

[youngunbd]

Welp my stuff is on the fritz again! A few weeks ago I rebuilt my turbo and re-installed it, when I tried to start the truck, she didn't start! So I began looking into what the heck it could be. First we put a jumper in the clutch position sensor, and that didn't do it, then we discovered it was the ignition mis-adjusted. Well I left the jumper in anyways cause I forgot about it. Haven't adjusted the ignition either, it's a pretty good anti-theft mechanism!

Well apparently when you put a jumper in a CPS, it likes to blow the 5 amp fuse that controls your dash lights and all. So I have been driving by feel at night since then hehe until last night! I changed the oil, replaced my headlights and took the jumper out and re-connected the CPS, put in a 5 amp fuse and voila, dash lights again!

Now here's the issue, when you turn the lights on, the radio turns off

First I thought it was the trigger wire, but then I noticed when the lights are on then off, the radio comes back up in demo mode since it was completely reset, which makes me think it's the constant 12v wire has an issue. But I took it right off the old deck...

I will get back there with the test light this evening when it cools off, but what in the world would cause my 12v constant to cut out when the light switch is pulled? Does it with running lights and headlights.

If I can't figure it out real quick tonight, I'll find another 12v since I'm making a 2 day trip starting real early tomorrow morning, then I can figure this all out when I get back.

Thank you all in advance!

 

[79jasper]

Sounds like a ground issue to me.

 

[MIDNIGHT RIDER]

Bypassing the clutch switch should have nothing whatsoever to do with any other electrical function.

As for your other issues, my best not-actually-being-there guess is that you have a badly corroded or loosely connected terminal in ---most likely--- the main HOT junction at the starter-solenoid/relay or at the ignition-switch; or, as already suggested, a GROUND issue.

 

[theguruat12]

One of the 15 amp fuses in the box controls my courtesy lamps and my radio, and it likes to give me funny business now and again. I would check all of your fuses first, but to me it sounds like the headlight switch; they're notorious for melting, and it could be shorting something out since the power for one of the feeds through the switch controls the radio as well. Other than that, a ground issue is all I can think of, and it's pretty likely that's the issue. I've had lots of them on my truck, especially near the dash, until I started tightening them all down after the PO's monkeying with all of the electrical system.

 

[MIDNIGHT RIDER]

There is one more place I would sure be looking when stuff is coming ON when it should be OFF and fuses are blowing when they have nothing to do with what seemingly blew them ----


Located in that big impossible-to-access *** of wires that proceeds out of the fuse-block and eventually to the head-light switch is a tiny TAN wire that is maybe 26-AWG and should have been at least 10-AWG.

Trucks of your vintage are notorious for that wire melting itself completely out of it's insulation and then melting into other wires.

Whether this is your problem or not, it would be wise to find it and replace it in it's entirety with a wire of much larger gauge.


When I learned about this truck-burning wire, I looked outside in the middle of the night to see all of my parking-lights lit up like a Christmas tree; the switch was OFF and nothing short of turning OFF the big battery switch would kill the lights.

When I found the problem, that tan wire was melted entirely free of it's insulation, from one end to the other, and had melted itself into an always HOT wire.

A 12-AWG wire has stood in it's stead since.