Lights Problem...

[WRKTRUK]

I have a 1984 C-10 Longbed, completely stock wiring wise, but with a 355 in it to keep up with the Mustang GT's on the interestate. Anyway to the topic at hand, last week as I left work I turned the lights on and when I did a blue spark went across the lower dash (metal part) right at the headlight pull switch. Well at that time my gauge cluster lights and tail lights immediately quit working. My interior dome lights come on when I turn my head lights on, but are very dim and brighten up when I shut them off, but the interior lights are ALWAYS on now unless the truck is off. 1st thing done with no testing was I replaced the head light switch, well that didn't change a thing. I checked and replaced any and every fuse that even remotely looked bad, still nothing. Well last resort I have another gauge cluster out of an 85 truck that I know works so I plugged it in and STILL nothing different. So here I am looking into the vast amount of knowledge on this site to direct me where to look next, or what to test/replace next. I have searched the electrical section with nothing but questions about 67-72 truck problems, so hopefully this section will get me the feed back I need.

Thanks in advance,
Ryan

Oh yeah, last thing the stuff that works fine is the headlights both bright and dim, the blinkers both inside and outside front and rear (including the green lights in the cluster), and the Blue lights in the cluster indicating that the bright light are on.

[flamingbig10]

I would check for any loose or unhooked wires under the dash and any shorted out wires

[Sniper X]

DC does weird stuff when it shorts, and usually in a car when it shorts it throws a spark, and burns the insulation off of some of the wires that short. DC especially when it is enough current to run lights, which draw a LOT of current, burns insulation off whihc usually leads to a dirrect ground short, that blows a fuse, or worse yet, causes a fire. In your case, Ill bet some wiring that is close together burned enough insulation off to connect themselves together. Get a wiring diagram and look at which wires go under the dash color wise and see what wires go to the effected areas. I can tell you that the wires from the brake light switch are right under the center of the dash on the switch and run in to a loom that goes back to the headlight switch for power. Look under the dash for any wires that look burned, and then trace them to find where the burn is and pull them apart and replace the insulation with shrink wrap. PLEASE do this with the battery disconnected or you might just make it works or even cause a fire.

[WRKTRUK]

Hey guys thanks for the quick responses. I am at work now and will update as to what I find when I can get back under the dash. The question I do have is if ANYONE has the diagram on hand of this particular part of my truck, I would happily paypal someone if it costs something or if it can be pm'd to me or whatever. I am waiting quite patiently for the shop manual I ordered off ebay but the problem I'm having is I am supposed to haul a car this weekend and have no way to get my trailer lights working with the problems inside my truck. Any help is appreciated, but hell I can't blame you if you wanna charge me for it, and again will gladly paypal money if this is available, if not I am actually a patient man and will wait. Again thanks guys for responding so quickly.

Thanks again,
Ryan

[Sniper X]

It will be very similar to this:

[WRKTRUK]

Thanks so much sniper I will keep yall updated on what I find out hopefully this afternoon if the rain slacks up, but for sure tomorrow, because as I said earlier I have to move a car this weekend and all the lights need to work for my trailer because it's an overnight trip.

Thanks,
Ryan

[Sniper X]

Originally Posted by WRKTRUK

Thanks so much sniper I will keep yall updated on what I find out hopefully this afternoon if the rain slacks up, but for sure tomorrow, because as I said earlier I have to move a car this weekend and all the lights need to work for my trailer because it's an overnight trip.

Thanks,
Ryan

Good luck! let me know if you need anymore help.