Instrument Cluster Help!!! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

mister.freeze · 07-27-2004, 10:03 AM

When I turn the lights on in the Fox, the temp gage jumps to hot, the fuel gage drops to E and there are no instrument lights! What happened? I'm guessing there's a short along one of the cluster lights. Anybody got a diagram of thet gage wiring and cluster lights? Thanks.

donkey69 · 07-27-2004, 10:27 AM

Sounds like a guy might want to make sure its got a good ground.

mister.freeze · 07-27-2004, 11:31 AM

I'm guessing that might be the problem, ie a short... Why is it that most folks say a bad ground as their default response to electrical problems? In my experience, overloaded circuits, chafed wires, or trauma are the cause of problems. Bad grounds are rare. I'll pull the cluster and take a gander soon, though.

BobbyK · 07-27-2004, 11:38 AM

So the gauges work when the lights are off?

If so then things are being ground through the light switch.

When you turn on the lights and you now have power going through the switch,causing a short in the system.

Check for the small ground wire that attaches to the dash frame.It's there to ground out the gauge console.

mister.freeze · 07-27-2004, 12:55 PM

Is That Via The Cluster Harness Or A Separate Wire?

BobbyK · 07-27-2004, 04:43 PM

there should be a dedicated ground wire for you gauge harness.
It has a special wire clip on it that clips onto the lip of the dash.

BobbyK · 07-27-2004, 04:54 PM

Here's what the ground wire looks like.

mister.freeze · 07-27-2004, 04:53 PM

Thanks, all. I fixed it on my lunch break. I don't have the dedicated ground wire. One of the laminated wires on the cluster unglued itself and got laid over onto the next one last time I plugged in the cluster. I straightened it out, carefully plugged everything back, and it works like a charm.

mister.freeze · 07-27-2004, 04:58 PM

I'll look, but have never seen it. Certainly wouldn't hurt to have if I'm supposed to. Is that a '71 thing? The Fox is a '72...

BobbyK · 07-27-2004, 05:02 PM

Possibly,not sure though.
Glad you got it fixed though.

donkey69 · 07-27-2004, 07:24 PM

Glad to hear you got your wires uncrossed!!

**GMCPaul** · 07-28-2004, 03:55 AM

mister.freeze the ground wire is supposed to be on all dash clusters not just the 71, it is the black ground wire in the clusters wiring harness loom at it should terminate in a end exactly like the one ion the photo. Be sure that when you slide it on lip on underside of dash its on bare unpainted metal.
GMCPaul

07-27-2004, 10:03 AM	#1
mister.freeze Registered User Join Date: Dec 2003 Location: Houston, TX Posts: 733	Instrument Cluster Help!!! When I turn the lights on in the Fox, the temp gage jumps to hot, the fuel gage drops to E and there are no instrument lights! What happened? I'm guessing there's a short along one of the cluster lights. Anybody got a diagram of thet gage wiring and cluster lights? Thanks. __________________ '72 K5, known as 'the Fox.'

07-27-2004, 10:27 AM	#2
donkey69 JB-80 &quot;Twice as Good&quot; Join Date: Jun 2004 Location: Central, MN Posts: 354	Sounds like a guy might want to make sure its got a good ground. __________________ HEY NOW!

07-27-2004, 11:31 AM	#3
mister.freeze Registered User Join Date: Dec 2003 Location: Houston, TX Posts: 733	I'm guessing that might be the problem, ie a short... Why is it that most folks say a bad ground as their default response to electrical problems? In my experience, overloaded circuits, chafed wires, or trauma are the cause of problems. Bad grounds are rare. I'll pull the cluster and take a gander soon, though. __________________ '72 K5, known as 'the Fox.'

07-27-2004, 11:38 AM	#4
BobbyK Registered User Join Date: May 2000 Location: Petrolia,Ontario,Canada but working in Port Huron,Mi. Posts: 1,771	So the gauges work when the lights are off? If so then things are being ground through the light switch. When you turn on the lights and you now have power going through the switch,causing a short in the system. Check for the small ground wire that attaches to the dash frame.It's there to ground out the gauge console. __________________ 71 blazer,350SBC,approx.375HP,700R4,factory GM TPI.Dual electric fans,33x12.5x15 ATR on stock suspension. Petrolia,Ontario,Canada but working in Port Huron,MI. See ALL my Blazer pic's HERE

07-27-2004, 12:55 PM	#5
mister.freeze Registered User Join Date: Dec 2003 Location: Houston, TX Posts: 733	Is That Via The Cluster Harness Or A Separate Wire? __________________ '72 K5, known as 'the Fox.'

07-27-2004, 04:43 PM	#6
BobbyK Registered User Join Date: May 2000 Location: Petrolia,Ontario,Canada but working in Port Huron,Mi. Posts: 1,771	there should be a dedicated ground wire for you gauge harness. It has a special wire clip on it that clips onto the lip of the dash. __________________ 71 blazer,350SBC,approx.375HP,700R4,factory GM TPI.Dual electric fans,33x12.5x15 ATR on stock suspension. Petrolia,Ontario,Canada but working in Port Huron,MI. See ALL my Blazer pic's HERE

07-27-2004, 04:54 PM	#7
BobbyK Registered User Join Date: May 2000 Location: Petrolia,Ontario,Canada but working in Port Huron,Mi. Posts: 1,771	Here's what the ground wire looks like. __________________ 71 blazer,350SBC,approx.375HP,700R4,factory GM TPI.Dual electric fans,33x12.5x15 ATR on stock suspension. Petrolia,Ontario,Canada but working in Port Huron,MI. See ALL my Blazer pic's HERE

07-27-2004, 04:53 PM	#8
mister.freeze Registered User Join Date: Dec 2003 Location: Houston, TX Posts: 733	Thanks, all. I fixed it on my lunch break. I don't have the dedicated ground wire. One of the laminated wires on the cluster unglued itself and got laid over onto the next one last time I plugged in the cluster. I straightened it out, carefully plugged everything back, and it works like a charm. __________________ '72 K5, known as 'the Fox.'

07-27-2004, 04:58 PM	#9
mister.freeze Registered User Join Date: Dec 2003 Location: Houston, TX Posts: 733	I'll look, but have never seen it. Certainly wouldn't hurt to have if I'm supposed to. Is that a '71 thing? The Fox is a '72... __________________ '72 K5, known as 'the Fox.'

07-27-2004, 05:02 PM	#10
BobbyK Registered User Join Date: May 2000 Location: Petrolia,Ontario,Canada but working in Port Huron,Mi. Posts: 1,771	Possibly,not sure though. Glad you got it fixed though. __________________ 71 blazer,350SBC,approx.375HP,700R4,factory GM TPI.Dual electric fans,33x12.5x15 ATR on stock suspension. Petrolia,Ontario,Canada but working in Port Huron,MI. See ALL my Blazer pic's HERE

07-27-2004, 07:24 PM	#11
donkey69 JB-80 &quot;Twice as Good&quot; Join Date: Jun 2004 Location: Central, MN Posts: 354	Glad to hear you got your wires uncrossed!! __________________ HEY NOW!

07-28-2004, 03:55 AM	#12
GMCPaul Senior Member Join Date: Mar 2000 Location: Rockville,In. USA Posts: 3,721	mister.freeze the ground wire is supposed to be on all dash clusters not just the 71, it is the black ground wire in the clusters wiring harness loom at it should terminate in a end exactly like the one ion the photo. Be sure that when you slide it on lip on underside of dash its on bare unpainted metal. GMCPaul __________________ Secure Online Catalog for-GMCPauls Truck Parts Email- GMCPAULS@GMAIL.COM

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