Instrument cluster possessed

Stereo, security systems, vehicle electronics, and electrical-related discussions
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ultrap
Posts: 5
Joined: Thu Oct 07, 2010 3:40 pm
Location: Leander, TX

Instrument cluster possessed

Post by ultrap »

I have a weird instrument cluster problem in my '04 GT 6sp. Hoping someone can shed some light on what could be causing it and maybe suggest a workaround fix.

Started as no illumination, no ODO, no gauges (speedo, tach, temp, fuel). Everything else worked OK including the instrument panel indicators like turn signals, hi/lo beam, ABS, CEL, BRAKE, OIL, SRS, etc.

Checked all fuses, especially AM2, GAUGE and DOME, all were good, replaced with new fuses anyway, no change. While I was replacing the fuses I stumbled on some strange behavior:

When I pull the DOME fuse and leave it out, the instrument panel starts working again! Speedo, fuel, illumination and all! Sometimes the gauge needles jump to 50% for a second when I first turn the ignition key. Other than that the whole instrument cluster works great...I drove the car like this for 2 weeks and the instrument panel worked fine the whole time. Of course with the DOME fuse removed I have no power to the radio, dome light and remote door locks which kinda sucks.

When I re-insert the DOME fuse, the instrument cluster only works until I turn off the car. After a few minutes with the key out, gauges and illumination go dead. I tried unplugging the Radio HU, no help. Another trick to temporarily bring the instrument cluster to life is unplugging the cluster harness and plugging it back in. Again then it works until I turn the car off for more than a few minutes.

I've been staring at the wiring diagrams but they're a bit overwhelming... My theory is that the DOME circuit provides permanent power to the instrument cluster, while the GAUGE circuit is switched. For some reason the permanent power connection is causing a problem in the cluster. I'm tempted to cut the wire providing power to the cluster from the DOME circuit rather than spend $$ on a new used cluster with incorrect mileage. Thoughts, anyone?
2004 Fusion Orange GT 6sp
2003 Silver GT 6sp
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Bookworm
Posts: 580
Joined: Fri Nov 05, 2010 11:21 am
Location: Houston, TX

Re: Instrument cluster possessed

Post by Bookworm »

It sounds like a short somewhere in the DOME circuit cluster, to me. Can't recall - does that feed the inverter or the 12 volt cigarette lighters?
ultrap
Posts: 5
Joined: Thu Oct 07, 2010 3:40 pm
Location: Leander, TX

Re: Instrument cluster possessed

Post by ultrap »

After careful consideration I decided to proceed with my plan and I cut the BLUE/WHITE wire on the instrument cluster harness (all the way on the right) thus removing permanent +12V supply from the instrument cluster on the DOME circuit. I then insulated both cut ends with heat shrink tape.

I'm happy to report that the instrument cluster is working again as are all loads on the DOME circuit (radio, remote lock/unlock, dome light, etc). I just got back from running some errands and everything is working great! Made 4 stops, spent over an hour shopping, instrument cluster came on every single time. The only differences from stock I observed so far are 1) no buzzer warning with the key out of the ignition and 2) the instrument cluster doing its initialization every time I insert the key. Both make perfect sense and are a logical consequence of pulling permanent +12V from the cluster.

I am declaring this problem fixed. $0 fix, one snipped wire. Hope it lasts.

Before I decided to cut the wire I looked for a short on the DOME circuit but couldn't find one. DOME fuse never blew. Tried disconnecting everything I could on the DOME circuit including the radio but the problem with the instrument cluster persisted. The only thing that would bring the cluster to life was unplugging it for a minute or pulling the DOME fuse. I also removed the cluster, took it apart and examined the circuit board. No obvious problems. None of the 5 capacitors appear puffed up indicating failure. I don't own an ESR meter so I couldn't test the capacitors in circuit but I suspect one of them failed.
2004 Fusion Orange GT 6sp
2003 Silver GT 6sp
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Bookworm
Posts: 580
Joined: Fri Nov 05, 2010 11:21 am
Location: Houston, TX

Re: Instrument cluster possessed

Post by Bookworm »

You could always try replacing the caps - but it could also have been a mosfet or transistor shorting open. A short doesn't have to blow the fuse - it just has to be enough power to interrupt everything around it. There's been more than one board that I've re-capped and found that there were more problems. In fact, there's been at least one that when bypassed, it went boom.

I just had a cap go boom in the attic, less than 20 minutes after installing the bulb. (Deliberately installed dirt cheap dollar store bulbs - it's for an attic string of lights which will probably only be used once every few weeks, for less than an hour at a shot. Just tired of going up there and not being able to see anything)

Frankly, the only ways to really test are expensive equipment, lots and lots of experimentation, or grabbing a cluster out of a junk car.
andrewclaus
Posts: 375
Joined: Tue Oct 03, 2017 6:38 pm
Location: Golden, CO

Re: Instrument cluster possessed

Post by andrewclaus »

I also think you're right suspecting a failed component in the CM. Maybe a diode.
Camaroboy
Posts: 1
Joined: Sun Oct 17, 2021 7:06 pm

Re: Instrument cluster possessed

Post by Camaroboy »

I had exactly the same symptoms with the instrument cluster in my 2003 Vibe. I figured what the hell and took your advice and cut the blue and white wire. Problem solved. It has been well over a month now and aside from the gauges cycling when the car is started I have had no more problems with the instrument cluster. (EXCEPT for 299999)Thanks so much for taking the plunge and being the first guinea pig for this wire snipping cluster cure.
Just curious though...is your gauge pod still good now?
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