[tdogzjoint]

My temp gauge has not worked since I did the digital cluster repair a few weeks ago, the needle spikes up when you start it, but after that drops to nothing( the bottom of the gauge ). At first I suspected the temp. sensor on the water pump was bad, but if I unplug the sensor, the CEL comes on, which makes me think it's still working, or does this happen just cause it's unplugged? Also, could I have fudged up the needle during the cluster repair?

 

[Scott Knight]

Wrong sensor. The one in the water pump is for the PCM and the one in the head right by the dipstick is for the gauge.

 

[bbsmoov]

The Temp sensor that controls the guage is in the back of the passenger head. The sensor on the water pump controls the electric radiator fans.

 

[tdogzjoint]

Oh, thanks, Ill check it out in the morning

 

[snakey5138999]

It seems these temp sensor ish the bed as soon as the gauge cluster gets removed....Mine did the same thing and even after replacing the sensor it still doesnt work. It started to happen right after i put LEDs into my cluster.

 

[tdogzjoint]

"It seems these temp sensor ish the bed as soon as the gauge cluster gets removed"

Huh?, do you mean sh*t the bed?

Are you trying to say that it is common for this to happen after a cluster repair?
When I put it back I know I messed up the oil pressure needle, as it now sits down so low you can't see it anymore, I was wondering if there's a way to reset their position since it just seems to be out of whack.

 

[tdogzjoint]

Does anyone have a pic or a diagram of where the sensor is, I coudn't find it earlier...

Thanks,
Tony

 

[bbsmoov]

Coolant Sensor location -
When you are standing in front of the car looking into the engine compartment, it is on the back of the passenger head on the left side of the head.

Unplug the pigtail and take a deep socket or wrench to remove it. Some coolant will spill.

 

[tdogzjoint]

When you are standing in front of the car looking into the engine compartment, it is on the back of the passenger head on the left side of the head.

Okay, is it this one?

 

[snakey5138999]

Yes, that is the one.

 

[rogers9c1]

same thing happen to me but not when I touched the gauge, I touched the connector and it just fell off leaving two prongs sticking out and a dead gauge. anymore of the cutaway LT1?

 

[mavf16]

Gents

95 Impala SS, LT1, 86K miles. I have the same symptom as original poster - temp guage full hot at crank, full cold with no movement when done cranking, never moves again while running. I replaced the correct sensor once already (in the head, with the correct temp sensor) and the wiring doesn't look or feel like that's the problem (as far as I can run my hand on it, anyway). Wondering if there is a way to put a voltmeter on the sensor (with the pigtail unplugged) to try to verify if that is actually working and I need to isolate my search to the wire? Does the voltage rise as the water temp increases? If yes, approximately what should the reading be?? Is there an easy way to check the continuity of the wire? If I check with an ohm meter, with one contact on ground, should there be an open circuit with the pigtail? This is driving me crazy and I've searched multiple forums with good hints but no "ah hah" solution. I know (well, suspect) it has to be the sensor, but can't figure out why the new one didn't do the trick. I think I may have dropped the new one before installing. Any way that could have messed it up before I even got it in?? Any ideas or help GREATLY appreciated.

 

[iCajun]

I haven’t touched the temperature sensors in the Impala but I learned far more than I ever wanted to know about them getting the gauges in my GM powered truck and boat working last Summer. Assuming it is the sensor I think it is, the resistance should vary pin to pin from about 29,000 ohms at -4 degrees to 180 ohms at 212 degrees. Not sure but I think the top of the gauge is around 262 degrees and 82 ohms. Translated, an open connection should peg the gauge low and a short should peg it high. So grab your ohm meter and unplug the sensor, at 77 degrees look for roughly 2830 ohms at the sensor. Most sensors seem to use a 5 volt input. Alligator clips and bent paper clips with a voltmeter work about as well as anything for checking the connector voltage. I eventually got a potentiometer so I could check the gauge indication vs resistance. Pretty cheap at Radio Shack. As I found out the hard way, there are some variations in two wire sensors. Hopefully you have the correct one installed as the parts guys don’t always get it right when buying replacements. I think yours is measuring resistance between the two pins. Others reference from each pin to ground and I have heard of some problems when using teflon tape to install the sensors. Some have dual sensors, that is each pin measures resistance to ground, two sensors in one, one for the gauge and one for the computer. Some are resistance to ground on one pin and a temperature switch to ground on the other for the idiot light. Note, oil pressure sensors are kind of the same arrangement, another bad experience with buying the wrong parts.

 

[scheme286]

Yes, that is the one.

is the sensor thats in the head the same p/n as the sensor in the pump? if not where can i get one. i changed the sensor in the pump but I didn't change the pigtail. on one side of the connector looks a lil rusted so i dont know if there is a bad connection