Instrument Cluster Lights will not turn off

[TripleBlackTermi]

Hello all,

New to SVTP and don’t use the site often so forgive me if I have done this wrong. I am in need of assistance. I have an 03 Cobra convertible which has the instrument cluster lights stuck on. This includes the HVAC control illumination as well as fog light on indicator. The map lights in the mirror will NOT turn on either by switch or door ajar. The instrument cluster is at max brightness and will not dim. It also appears the parking lights and fog lights will not turn off. The front bumper with fog lights is off the car currently so I plugged in both headlights for testing purposes and confirmed the parking lights to be on and not turning off. This is in conjunction with the fog light on indicator light on the fog light switch being on with the headlight switch off. I suspected a faulty headlight switch so I removed the headlight switch. The the switch removed the cluster, HVAC, interior switch lighting, and headlamps all went off, however the fog light on indicator remained illuminated. The car has Autometer Boost/AF wideband/digital shift light control, all of witch I have removed via the add-a-circuit and replaced the fuse for in an effort to eliminate a potential source of the malfunction to no avail. At this point I am at a complete loss. Any help is appreciated.

 

[MG0h3]

First thing I’d do is inspect the headlight switch plug and wiring going into it. Do you see any signs of heat?

If so, you’ll need to replace that.

At the same time, I’d grab a new headlight switch and install that to see if the entire problem comes back. Common sense says it should not. You could use a voltmeter and test the old one but not sure I’d bother.

Little strange that the fog light indicator is still on. I would’ve guessed that would receive it’s closed circuit via the headlight switch. But back to step one. Look for signs of heat like burnt plastic or wire insulation at the plug. After that I’d get a wiring diagram to see where that indicator gets it’s power


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[TripleBlackTermi]

Well problem solved and it was the dumbest thing and proof one should not work on a car while tired. The FPDM was unplugged while installing a BAP and I left it unplugged while waiting for parts. Apparently the lights were a warning indicator of some sort. I plugged it in as it was the only other wiring which was being worked on and everything went back to normal.

 

[MG0h3]

Ha nice.

Glad you figured it out.


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[CobraBob]

Don't you love endings like that. We all make similar mistakes all too often. I glad you didn't have to spend lots of time diagnosing a non-issue.

 

[CobraBob]

Site crawling. Sorry for the double post.

 

[TripleBlackTermi]

I was beyond thankful. I’ve had many mustangs over the years and usually the electrical problems don’t resolve in such a simple manor. What a dumb dumb mistake!

 

[CobraBob]

Call it a "memory lapse". Sounds better. LOL.

 

[TripleBlackTermi]

LOL I like it, I’ll go with that!