Instrument Cluster Not Working

MyLittlePony

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We removed the GT cluster out of my 94 when we removed the dash. Now that everything has been reassembled, it no longer functions. Everything lights up, including the needles when the headlights on, the battery indicator will come on and then off once the engine is running (only light on the bottom that lights up now. No check engine, seatbelt, or air bag light), but the needles remain in place. We swapped in my original V6 gauge that worked when removed in 08, and same result.

Edit: It’s blowing a fuse. #15. Going to start looking there.

Edit Edit: changing fuse from a 10 to a 15 fixes it
 
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07GtS197

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I read a thread saying it could be the headlight switch. There’s a short somewhere.
 

ttocs

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take the cluster back out and inspect the connections where the harness plugs into the back of the gauges. There are a bunch of copper traces that are known to lift and move and either not make contact or short something else out.
 
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MyLittlePony

MyLittlePony

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I read a thread saying it could be the headlight switch. There’s a short somewhere.

Head light switch merely controls illumination, which works.

take the cluster back out and inspect the connections where the harness plugs into the back of the gauges. There are a bunch of copper traces that are known to lift and move and either not make contact or short something else out.

The problem is a blown fuse, as mentioned. My husband wanted me to ask online what the problem might be, so I did. Once I realized that it’s not just the needle gauges but also system lights, I checked the fuse. Replacement 10s will blow, but a 15 amp won’t, and everything now works with a 15. He messed with the wiring so more goes through that one. I just couldn’t delete my thread once I figured that out.
 

07GtS197

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Yes but a few circuits associated with the instrument cluster lighting go through the headlight switch. I wouldn’t rule it out entirely. But I guess it doesn’t matter since you “fixed” it.
 

ttocs

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Head light switch merely controls illumination, which works.



The problem is a blown fuse, as mentioned. My husband wanted me to ask online what the problem might be, so I did. Once I realized that it’s not just the needle gauges but also system lights, I checked the fuse. Replacement 10s will blow, but a 15 amp won’t, and everything now works with a 15. He messed with the wiring so more goes through that one. I just couldn’t delete my thread once I figured that out.
If the stock 10 amp fuse is blowing there is a reason. The fact the 15 amp is not means that the circuit now has the ability to pull more power than it is designed to take and if/when it shorts out again you will probably end up replacing more than the 15 amp fuse.........
 

cobrajeff96

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Agreed. Best bet is to always keep aftermarket/custom things off OEM circuits. Not only are the fuses spec'd out for the given circuit, but so are the wire gauges (thickness). You can wind up overloading a circuit... and installing higher amperage fuses could wind up turning the wire itself into a fuse and thus a fire hazard.
 

ttocs

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it only allows the voltage/current to get %50 more power then the original before it blows how can that be bad? = sarcasm :)
 
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MyLittlePony

MyLittlePony

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Yes but a few circuits associated with the instrument cluster lighting go through the headlight switch. I wouldn’t rule it out entirely.

Except those few work and have no connection to the problem whatsoever. Turn the knob, interior lighting, including the gauges work. Adjust the knob, and the lightning brightens or darkens depending on the user. If nothing lit up, I would check the headlamp switch because I know I messed with it when removing the knob, and may have been turned in the dimmest position.

8FEF25DF-1BC9-4C4C-B6A1-7622997EC7C0.jpeg

As you can see, all that curcuit does is light the brake and high beam indicators. Not all the stuff that I was having an issue with. That fuse (#13) was fine.

763C4998-4713-40AE-BB02-34681870E080.jpeg

This is essentially everything that wasn’t working when I created this thread. Having #15 fuse blow pretty much indicates that this is where the problem is located.

If the stock 10 amp fuse is blowing there is a reason. The fact the 15 amp is not means that the circuit now has the ability to pull more power than it is designed to take and if/when it shorts out again you will probably end up replacing more than the 15 amp fuse.........
But I guess it doesn’t matter since you “fixed” it.

A short would blow a 15amp fuse and even 20 AWG wire will support 15 amps for a 16" run. This thread was created in hopes to locate the problem since diagnosis of everything else turned up nothing. It wouldn’t let me delete the thread, so I added the discovery of the fuse hoping that maybe at least it could help someone else in the future, since checking the fuses should be the first thing you do. Now that we know where the problem is, we can focus our attention there.

Agreed. Best bet is to always keep aftermarket/custom things off OEM circuits. Not only are the fuses spec'd out for the given circuit, but so are the wire gauges (thickness). You can wind up overloading a circuit... and installing higher amperage fuses could wind up turning the wire itself into a fuse and thus a fire hazard.

My husband ran a second 8 gauge power block straight from the battery into a fused distribution block with a relay for all this aftermarket stuff. Essentially while the dash was out, he was trying to clean up the 25+ years of spaghetti wiring it had accumulated throughout the years. Everything not Ford should be on that block, but I don’t know, which is why my husband can look at that specific circuit to see what’s up.

I feel that all my interior lighting should be on that new power block, but he did mention that my aftermarket reverse glow illumination cluster panel, which was always on when the car was on, now will only come on differently, so maybe that’s it.

Edit: He said he tapped the reverse glow to the illumination circuit on the back of the gauge cluster, and did that AFTER the blown fuse in hopes that would help him figure out why the gauges weren’t working. The V6 cluster has the same kit on it, but disconnected. It didn’t work because the fuse was still blown.
 
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cobrajeff96

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Is the glow feature LED? I know some LEDs don't play nice with variable resistor dimming feeds.
 

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