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Discussion Starter #1
Sorry this ones long.

On the car I'm building I lost all dash lights in the cluster, heater control etc and Im not sure how I did that. headlights and tail lights still work.

I know my dimmer and headlight switches are good, tried them in my other car and they work.

I'm thinking it's a bad ground but let's see if anyone else has any ideas.

The car is a 90.
I recently had the dash out to do the heater core, removed both the airbag module and airbag power supply, (It's mostly a drag car) and
removed the factory amp harness.

Hooked the batt back up and was going to test for dash light power for aftermarket gauge lights, but I didn't have any dash lights.

I tested for a while, pulled the entire dash back out again, the plastic portion, the steel dash framework is still bolted in, and with a lighted continuity test light I have been probing the headlight and Dimmer switches while they are connected. On my 93, on the dimmer switch the black w/blue stripe and green w/yellow stripe have solid continuity to ground with the headlight switch off, key off and batt unhooked. The 90 that I'm having issues with, both of those 2 wires have a very weak connection to ground with key off and batt un hooked.
Also those wires do not power up when the headlight switch is turned on. On the 93 they do power up.

On the headlight switch the large red w\ yellow stripe is not getting power when the headlight switch is turned on.

The relay is also working.

I tried hooking everything I removed back up. Nothing seemed to change until I hooked 2 plugs back up under the column. 1 for the ignition dinger and 1 for either the horn or airbag. (3 wire rectangular plug, its def not for cruise).
After that I had power again. I plugged the cluster back in to make sure and then it stopped working again. I went through all the wiring jiggling and shaking thinking I had knocked something loose or had a bad connection but I never could get it to come back.

Ive been messing with it for hours now and my brain is to tired to diag clearly anymore today.
 

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Discussion Starter #2
Forgot the cruise and horn are on the same round plug. So the one I hooked up must be for airbag.
 

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If you are missing a ground the entire circuit will have batt voltage right up to point the ground is missing
 

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Discussion Starter #4
Well let me ask you this, does the dash frameworks ground simply come from being bolted on either side and also to the pedal assembly or does it actually have any wires?

Ive pulled a bunch of these dashes and never ran into this before. I'm out here now, going to look and see if any connectors have broken and pushed the wires(s) out the back creating a bad connection
 

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Discussion Starter #5
Jeebus you would not believe what it was. Prev owner had those copper terminals that sandwich under a fuse so you can hook a wire directly to the fuse box. I thought I had removed them all but fuse 13 still had one that was broken off so it looked like it didn't have one. And there was some corrosion on it and the fuse. Pulled it, got a new fuse and a little dialectic grease and it seems to work fine now. Unbelievable. So I guess moral of the story is don't just rely on testing the fuse in the box with a test light. Because apparently I was getting a false positive connection.

I knew it was something stupid. I fully expected that I caused it somehow.
 

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That is why you do NOT move anything while testing

You might make a temp fix

Forget ohm tests

Voltage drop with intact energized circuits is the foolproof way
 
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