Interior Lights Electrical Problem

[conozo]

I need some help with figuring out where my electrical problem lies with the Interior Lights Fuse/Circuit

First of all i have done the carb to FI and auto to manual swap. What i have noticed after the swap is that the fuze was blown before and was replaced with a higher amp fuse. ( I wish i would have noticed this before i put it in the car to inspect the wiring) At first i had turned on the ignition with no problem then a day later i think i move the dash brightness knob up then when i turned the key on a fuse blew. I do not have any radio plugged in, no door lights, no cigarette lighter plugged in.

What do you guys think the problem is with or have any ideas on how to trace it.

[Oldblueaccord]

Well using a meter set to continuity would show a dead short. I dont think you have a short just high load.

I would find everything on that one curcuit and pull it all adding in one at a time.

A blown bulb could cause it.

I WOULD NOT use a bigger fuse to fix the problem as you noted.

[lostforawhile]

it could be the dimmer module failing might be why it blows the fuse when you turn up the brightness. the control is nothing but a potentiometer for the module, it doesn't directly control any current, even if the control shorted, the lights would simply go to full brightness, dimmer module is solid state, so maby an internal issue

[gp02a0083]

Doubt its the dimmer control. The dimmer's trim pot varies the resistance from 0 to 10k ohm. If there were a short it would act as a low resistance pathway similar to setting the trim pot to its lowest value or near 0 ohm. It sounds as if you have a nice short somewhere else to trace down being you mentioned it has a larger current rated fuse that keeps frying.

Should brush up on your electrical. A potentiometer is not a solid state device like a transistor or diode, it is an electo-mechanical device. Our dimmer modules are nothing more than a 10K trim pot.

[lostforawhile]

I'm talking about the module itself, it's under the plastic around the steering column, thats what directly controls the lights, and I know perfectly well how a pot works, all it does in this case is control that module, all red/black wires in the illumination circuit are going to be power from the illumination circuit, and all red wires in the circuit as variable ground from that module, in this case, if the OP has a spare module around, it's a simple test to plug in other one and see if it quits doing it, the fact that it happens at a certain point in the dimmer range says it's probably the module,

[gp02a0083]

Oldblue's suggestion of narrowing down the root of the problem by systematically removing components may end up being the way to diagnose the issue. However, to keep this thread on track and help you correctly rather than just blindly sourcing and replacing parts use the attached image and a multi meter to sort out whats going on. In addition please tell us exactly which fuse is blowing (i'm assuming illumination) and if the chime works (piggybacked to the module). BTW the BLACK WIRE IS GROUND and the red wire is the supply....

[lostforawhile]

Oldblue's suggestion of narrowing down the root of the problem by systematically removing components may end up being the way to diagnose the issue. However, to keep this thread on track and help you correctly rather than just blindly sourcing and replacing parts use the attached image and a multi meter to sort out whats going on. In addition please tell us exactly which fuse is blowing (i'm assuming illumination) and if the chime works (piggybacked to the module). BTW the BLACK WIRE IS GROUND and the red wire is the supply....

black wire is ground to the module, but the red is a variable ground, and red/black is illumination power, all the bulbs have 12 volts constant when on, but the ground varies to dim them, if you connect the solid red wire to ground the lights will come on full bright, I know in most systems red is hot, but in this case it signifies a controlled ground, A lot of people get confused trying to hook up gauges etc, due to that

[conozo]

I'm going to unplug everything then plug in one thing at a time. I dont think its the dimmer switch since I used the same one from my car. The only thing that came from the parts car which had the problem is the wiring harness and the instrument panel that is connected to this particular circuit. The fuse im talking about is the fusebox in the engine labelled Interior Lights.

[lostforawhile]

I'm going to unplug everything then plug in one thing at a time. I dont think its the dimmer switch since I used the same one from my car. The only thing that came from the parts car which had the problem is the wiring harness and the instrument panel that is connected to this particular circuit. The fuse im talking about is the fusebox in the engine labelled Interior Lights.

that fuse has nothing to do with the dash illumination

[lostforawhile]

your fuse for everything for position 1 of the headlight switch, is fuse 14 in the under dash fuse box, should be 15 amps. the fuse for the interior light circuit is fuse 13 in the under hood fuse box, you should have a white/blue wire coming into the cabin, it goes to a junction taped into the harness by the left side kick panel. then it goes to the the trunk light and to the dome light, the dome light grounds are controlled by the information center in the cluster, they aren't directly controlled by the door switches. the only one directly controlled is the trunk light, all other door switch wires are routed to the information center as inputs. I wouldn't suspect the information center unless it blew fuse 2 in the under dash fuse box, I suspect it's somewhere from the under fuse box through that junction connector then from there to either the trunk light or dome light