Temp gauge quit. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

N2Clsx · 06-19-2011, 04:29 PM

The wire from the temp gauge popped off of the sensor and set on the header for a day or so and the temp gauge was pinned to hot even with the key not in the truck. Well we moved the wire back to the sensor and the gauge went back to normal but now we get no reading at all. Could we have fried the temp gauge? Any advice?

Thanks, Ray

N2Clsx · 06-23-2011, 02:52 AM

Nobody?

MagmaJct · 06-23-2011, 07:28 AM

I have a few thoughts that I will share:

Measure the resistance of the sensor at various engine temps. (i.e. when cold, when hot.) It's not likely the sensor is damaged since a missing wire shouldn't fry that, but at least it can be eliminated.

Is the thermostat opening? When I first got my truck I found my temp gauge didn't work. I got a new sensor from Checker that didn't fit. (They insisted it was the right sensor!) Turns out my Uncle when he owned it, replaced the stock 195F thermostat with a 165F which kept the engine too cold to move the needle.

The odds are some damage was done to the gauge. Unfortunately I don't know how the gauge converts the sensor resistance to a needle movement. I'm thinking it would use a simple voltage divider using a resistor but again you would get no reading at all.

Is it possible the wire was damaged when it was disconnected, maybe under a sleeve or something?

cdowns · 06-23-2011, 07:36 AM

take wire off sender and ground the wire to the engine// that should cause gauge to peg at the max// if not then you either have a brokem wire or a bad gauge

N2Clsx · 06-23-2011, 02:27 PM

Quote:

Originally Posted by cdowns

take wire off sender and ground the wire to the engine// that should cause gauge to peg at the max// if not then you either have a brokem wire or a bad gauge

Thats exactly what happened. My son called to tell me that his temp gauge was pinned to hot and the engine wasnt running. I told him to drive it home and we will take a look. Well we found the tip resting on the header. We put it back on the sensor and have not got a reading since.

imdarren · 06-23-2011, 03:03 PM

Copper wire is a great heat transmitter.
Possibility -
The terminal resting on the header sent heat up the wire and could have melted the insulation at another point align the wire. If the wire is grounded out somewhere, the gauge will stick at hot. Inspect the wire up further and make sure it's ok, not melted, and not grounded out.

Darren

06-19-2011, 04:29 PM	#1
N2Clsx Registered User Join Date: Jun 2000 Location: San Dimas CA Posts: 43	Temp gauge quit. The wire from the temp gauge popped off of the sensor and set on the header for a day or so and the temp gauge was pinned to hot even with the key not in the truck. Well we moved the wire back to the sensor and the gauge went back to normal but now we get no reading at all. Could we have fried the temp gauge? Any advice? Thanks, Ray

06-23-2011, 02:52 AM	#2
N2Clsx Registered User Join Date: Jun 2000 Location: San Dimas CA Posts: 43	Re: Temp gauge quit. Nobody?

06-23-2011, 07:28 AM	#3
MagmaJct Registered User Join Date: May 2008 Location: Mesa, AZ Posts: 281	Re: Temp gauge quit. I have a few thoughts that I will share: Measure the resistance of the sensor at various engine temps. (i.e. when cold, when hot.) It's not likely the sensor is damaged since a missing wire shouldn't fry that, but at least it can be eliminated. Is the thermostat opening? When I first got my truck I found my temp gauge didn't work. I got a new sensor from Checker that didn't fit. (They insisted it was the right sensor!) Turns out my Uncle when he owned it, replaced the stock 195F thermostat with a 165F which kept the engine too cold to move the needle. The odds are some damage was done to the gauge. Unfortunately I don't know how the gauge converts the sensor resistance to a needle movement. I'm thinking it would use a simple voltage divider using a resistor but again you would get no reading at all. Is it possible the wire was damaged when it was disconnected, maybe under a sleeve or something?

06-23-2011, 07:36 AM	#4
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	Re: Temp gauge quit. take wire off sender and ground the wire to the engine// that should cause gauge to peg at the max// if not then you either have a brokem wire or a bad gauge __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

06-23-2011, 03:03 PM	#6
imdarren Registered User Join Date: Oct 2001 Location: SW Washington Posts: 1,006	Re: Temp gauge quit. Copper wire is a great heat transmitter. Possibility - The terminal resting on the header sent heat up the wire and could have melted the insulation at another point align the wire. If the wire is grounded out somewhere, the gauge will stick at hot. Inspect the wire up further and make sure it's ok, not melted, and not grounded out. Darren __________________ Washington State 1967 Chevy C10 LWB Rodstoration In Progress. 1972 K20 Cheyenne Super



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