REM Clock Showing -F° Coolant Temp

[White_Comanche]

For anyone who has a version of Nick's REM installed I'd like to know if you guys have noticed this.

 

My coolant temp reading suddenly began show negative -F° values with a cold engine. As the engine warms up to operating temperature the reading doesn't correct itself. The most recent drive it topped out to only 75° when hot.

 

The actual temp gauge appeared normal showing 195° to 200°.

 

I contacted Nick through FB, and after some back and forth he though I may benefit from replacing my Coolant Temp Sensor.

 

HOWEVER, the resistance readings of my CTS appeared accurate. Showing 2,400 to 2,500 with it being 'cold' in an 80°ish degree garage.

 

 

 

[Ωhm]

3 hours ago, White_Comanche said:

The most recent drive it topped out to only 75° when hot

 

3 hours ago, White_Comanche said:

HOWEVER, the resistance readings of my CTS appeared accurate. Showing 2,400 to 2,500 with it being 'cold' in an 80°ish degree garage.

 

Disconnect CTS. Reconnect your DVOM across CTS. Measure Ω’s with COLD engine. As engine HEATS up, look for Ω values to decrease. Once engine reaches Normal Operating temperature, DVOM should show less than 1000 Ω’s.

[White_Comanche]

23 minutes ago, Ωhm said:

Disconnect CTS ... Reconnect DVOM across CTS ... As engine HEATS up, look for Ω values to decrease

Thanks Ohm. I will do this test when my truck is operational again. Have a no-start issue that is plaguing it... I currently have an active post figuring that out.

 

This test earlier was static with the truck just sitting in the garage unable to run. Garage air was roughly in the low 80s. Thinking that my REM may be corrupt.

[White_Comanche]

My REM Clock suddenly has corrected itself. So far it continues to show positive and correct F° values.

 

I didn't bother to disconnect the CTS and read resistance. Because I could see the F° values matching what the coolant gauge was showing as the engine was warming to operating temp.

 

I'll continue to keep this post up, incase others come across a wonky temp reading on their REM.

[White_Comanche]

FOLLOW UP:

Think I may know the reason why my REM suddenly "corrected itself" by showing accurate coolant temps.

 

During the weekend I cleaned and re-seated my +positive battery cable.

 

Not only did this solve my REM showing negative coolant values, but it also allowed my truck to start (I've had a nagging and random no-start issue).

 

Soon, both my positive and negative cables will be replaced. Both are very old, and they also have exposed copper wires.