Water temperature Gauge - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Paul83 · 11-08-2014, 11:35 PM

I am having a problem with my factory temperature gauge. It is staying on the cold side and will not move. I have tried the grounding it out method and it did not move so I tried an extra temp gauge I had and it did the same thing. (needle did not move) I can't think that both gauges are broken and I have put on 2 separate temperature sending units nothing. I also tested the ohms on the ceramic piece behind both of the gauges and they are both reading 84 ohms. I have installed electric fans recently. I don't think the engine temp is staying below 100 degrees. Is there a wiring issue somewhere. Maybe I don't have it grounded good enough what do you think? All the other gauges work except my gas gauge. I am not sure if they are related or not. Any thoughts or input is helpful. Thank you.

greg64 · 11-09-2014, 12:39 AM

Paul, sounds to me like either the wire from the gauge to the sender is broken somewhere, or the gauge isn't receiving 12V power. The sender wire is dark green, to my memory. It goes thru the firewall connector, and I think that's the only break in it. Do you have the instrument cluster apart?

Paul83 · 11-09-2014, 01:01 AM

It is not completely apart. I just have the front covers off to take out the temp gauge.

greg64 · 11-09-2014, 10:29 AM

Paul, if you have a multimeter, you can put it on ohms and probe between the sensor wire and ground. It'll read between about 100 ohms to a few thousand, depending on the temperature. I'm thinking you could back probe the wire where it goes thru the firewall, and then you'll know if the engine side is the problem or the dash side. You can also test right at the sensor.

chengny · 11-09-2014, 08:38 PM

Check as below:

Standard GM temp/resistance values for air/coolant sensors:

Check that the sensing leg (dark green lead) is intact. Pull connector from sender and ground to engine block. Then check the dash end for continuity to the frame. A broken sensing lead will keep the gauge pegged at the low end.

Paul83 · 11-10-2014, 12:08 AM

Thank you chengny and greg. I found the break in the wire. I must have pinched part of the wire when I installed the transmission or something.

11-08-2014, 11:35 PM	#1
Paul83 Registered User Join Date: Dec 2012 Location: Humble, TX Posts: 171	Water temperature Gauge I am having a problem with my factory temperature gauge. It is staying on the cold side and will not move. I have tried the grounding it out method and it did not move so I tried an extra temp gauge I had and it did the same thing. (needle did not move) I can't think that both gauges are broken and I have put on 2 separate temperature sending units nothing. I also tested the ohms on the ceramic piece behind both of the gauges and they are both reading 84 ohms. I have installed electric fans recently. I don't think the engine temp is staying below 100 degrees. Is there a wiring issue somewhere. Maybe I don't have it grounded good enough what do you think? All the other gauges work except my gas gauge. I am not sure if they are related or not. Any thoughts or input is helpful. Thank you. __________________ I don't care how old or gangster you think you are; if a 3 year old hands you a play phone you answer that! I like long walks on the beach, dinner by candle light, and poking dead things with a stick.

11-09-2014, 12:39 AM	#2
greg64 Registered User Join Date: Dec 2007 Location: Kimberley, BC, Canada Posts: 799	Re: Water temperature Gauge Paul, sounds to me like either the wire from the gauge to the sender is broken somewhere, or the gauge isn't receiving 12V power. The sender wire is dark green, to my memory. It goes thru the firewall connector, and I think that's the only break in it. Do you have the instrument cluster apart? __________________ Greg 64 GMC Suburban - 283, NV3500, 14 bolt 77 C10 swb - 292, SM465, 12 bolt

11-09-2014, 01:01 AM	#3
Paul83 Registered User Join Date: Dec 2012 Location: Humble, TX Posts: 171	Re: Water temperature Gauge It is not completely apart. I just have the front covers off to take out the temp gauge. __________________ I don't care how old or gangster you think you are; if a 3 year old hands you a play phone you answer that! I like long walks on the beach, dinner by candle light, and poking dead things with a stick.

11-09-2014, 10:29 AM	#4
greg64 Registered User Join Date: Dec 2007 Location: Kimberley, BC, Canada Posts: 799	Re: Water temperature Gauge Paul, if you have a multimeter, you can put it on ohms and probe between the sensor wire and ground. It'll read between about 100 ohms to a few thousand, depending on the temperature. I'm thinking you could back probe the wire where it goes thru the firewall, and then you'll know if the engine side is the problem or the dash side. You can also test right at the sensor. __________________ Greg 64 GMC Suburban - 283, NV3500, 14 bolt 77 C10 swb - 292, SM465, 12 bolt

11-09-2014, 08:38 PM	#5
chengny Registered User Join Date: May 2007 Location: New Hampshire Posts: 349	Re: Water temperature Gauge Check as below: Standard GM temp/resistance values for air/coolant sensors: Check that the sensing leg (dark green lead) is intact. Pull connector from sender and ground to engine block. Then check the dash end for continuity to the frame. A broken sensing lead will keep the gauge pegged at the low end.

11-10-2014, 12:08 AM	#6
Paul83 Registered User Join Date: Dec 2012 Location: Humble, TX Posts: 171	Re: Water temperature Gauge Thank you chengny and greg. I found the break in the wire. I must have pinched part of the wire when I installed the transmission or something. __________________ I don't care how old or gangster you think you are; if a 3 year old hands you a play phone you answer that! I like long walks on the beach, dinner by candle light, and poking dead things with a stick.

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