electrical problem

[jbmar]

i own a 91 that i just got off of a friend,it runs but im trying to work out a few bugs and one of them is when i turn the ignition switch to on position the tail lights and heater control panel come on, could someone please point me in the right direction.

[blazer_guy86]

I would start out by taking a look at all the factory wiring to see if it has been messed with. Other than that i'm clueless here.

[RahX]

what do you mean by the heater control panel comes on? it sounds like it could be a problem with either the ignition switch, either the heater and/or the headlight switch. being a 91 it could be multiple problems. The first thing i would do is look at the radio. yea it sounds weird but if its aftermarket make sure the goon who put it in didnt just hook it up wrong. I wired mine up in such a way that if i turn the headlights on, even without the key in the ignition, the radio works. It was intentional but it was very easy to do. the headlights are hot all the time and the heater happens to be hot in run....

[jbmar]

the heater panel lights up as if i turned on the tail light switch.

[RahX]

ah, sounds like you might have a bad headlight switch. an old trick we used to use if we were lazy at the shop was to order another one up and without marking it up like we used it, we would test the part and if it worked yay we saved some diagnostic time. if not we would just send it back later saying we didnt use it :P.

[jbmar]

if i unplug the headlight switch,turn ignition to on and the tail lights and heater DONT light,will that tell me the headlight switch is the problem?

[RahX]

it tells me that there is something in that circuit that is doing it. your truck is a 91, what engine, is it 4x4, does it have daytime running lights?

[jbmar]

its a 2.5,5 speed,2 wheel drive,not sure,dont think it would have daytime running lights.

[RahX]

also, what kind of gauges does it have? digital or regular analog?

[jbmar]

regular gauges

[RahX]

ok on the headlight switch there is a brown wire which feeds the tail lights. backprobe the switch (after youve taken it out of the dash with it plugged in) on that wire and see if youre getting power there. if youre looking at the back of the connector it should be on the very right with the ____-____ up, tab whatever you wanna call it. anyway if youre getting power there with it plugged in and not turned on, just the key on then unplug it and retest. lemme know what you get key on engine off/key off etc.

[jbmar]

i had no power key off switch off
it had power key on switch off,couldnt get correct voltage truck was hooked to a battery charger.I also noticed the tail and dash lights wont work by using the switch, with the key off,the only way the tail and dash light up is when i turn the key on,(switch off).