Need to verify temp. gauge malfunction... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Southpa · 02-12-2004, 08:15 PM

...before I go buy a new one. The gauge is pegged all the way to the hot side whether the green wire is attached to the sensor or not. I checked for continuity between the sensor clip and the gauge and I get a reading so the wire from sensor to gauge is ok. Any advice?

tom hand · 02-12-2004, 08:30 PM

Is the gauge pegged when the key is off?

Longhorn Man · 02-12-2004, 09:26 PM

Follow that green wire into the engine compartment. You'll probably find that it is melted or chafed some place and shorting to ground.

Southpa · 02-12-2004, 09:30 PM

Its pegged under any conditions, does not move, not even a twitch. I just bought another mech. gauge/sensor setup, will install it tomorrow. I previously went through 3 Equus brand mech. setups and they lasted about a year each time. This time I went a step up and got a Sunpro whiteface. But I'd still like to have the stock setup operational. My local supplier quoted me 50 bucks Cdn for a stock replacement gauge along with a 3 week wait. A little steep IMO.

Longhorn, the wire is good between the sensor and the gauge cluster, checked with an ohmmeter.

Longhorn Man · 02-12-2004, 10:54 PM

If the guage is staying pegged when the ignition is off, it is probably a bum guage.
ON the wire testing, did you connect a lead to one end of the wire, and then the other lead to the engine block? That would test for a short to ground.
If you just did from one end of the wire to the other end, then it would test good but could still have a short to ground. The continuity would still flow in the wire, but it would also go through the short too. And since the guage works off of Ohms to ground, if you ground out the wire (say a melted section on the exhaust manifold) then the guage would peg out to hot.

02-12-2004, 08:15 PM	#1
Southpa Registered User Join Date: May 2000 Location: Victoria, BC, Canada Posts: 2,410	Need to verify temp. gauge malfunction... ...before I go buy a new one. The gauge is pegged all the way to the hot side whether the green wire is attached to the sensor or not. I checked for continuity between the sensor clip and the gauge and I get a reading so the wire from sensor to gauge is ok. Any advice? __________________ 1970 GMC 1500 Custom Original 350/TH350 Victoria, BC, Canada You can wish in one hand and crap in the other. See which one gets filled first.

02-12-2004, 08:30 PM	#2
tom hand CCRider Join Date: Feb 2000 Location: Olive Branch,MS,USA Posts: 2,232	Is the gauge pegged when the key is off? __________________ 72 GMC Sierra SWB almost finished---- 84 Softail Olive Branch MS

02-12-2004, 09:30 PM	#4
Southpa Registered User Join Date: May 2000 Location: Victoria, BC, Canada Posts: 2,410	Its pegged under any conditions, does not move, not even a twitch. I just bought another mech. gauge/sensor setup, will install it tomorrow. I previously went through 3 Equus brand mech. setups and they lasted about a year each time. This time I went a step up and got a Sunpro whiteface. But I'd still like to have the stock setup operational. My local supplier quoted me 50 bucks Cdn for a stock replacement gauge along with a 3 week wait. A little steep IMO. Longhorn, the wire is good between the sensor and the gauge cluster, checked with an ohmmeter. __________________ 1970 GMC 1500 Custom Original 350/TH350 Victoria, BC, Canada You can wish in one hand and crap in the other. See which one gets filled first.

02-12-2004, 09:26 PM	#3
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Follow that green wire into the engine compartment. You'll probably find that it is melted or chafed some place and shorting to ground.

02-12-2004, 10:54 PM	#5
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	If the guage is staying pegged when the ignition is off, it is probably a bum guage. ON the wire testing, did you connect a lead to one end of the wire, and then the other lead to the engine block? That would test for a short to ground. If you just did from one end of the wire to the other end, then it would test good but could still have a short to ground. The continuity would still flow in the wire, but it would also go through the short too. And since the guage works off of Ohms to ground, if you ground out the wire (say a melted section on the exhaust manifold) then the guage would peg out to hot.



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