Testing Your Temperature Gauge Write-Up

[wesbest96]

On the Vortec 350 engine there are two coolant temperature sensors. One for the PCM and one for the dash. #1 is for the PCM and by the thermostat. #2 is for the dash and is by sparkplug #1 but connected slightly higher than that.
http://s1337.photobucket.com/user/Wes_Best/media/1223111605_zps36ae87df.jpg.html

Disconnect sensor #2 with key out of ignition. Place one end of jumper wire in the connector that isn't coming out of block. My wire was fusible with alligator clips. Like this

http://s1337.photobucket.com/user/Wes_Best/media/Snapchat-20140219103306_zps6e983c96.jpg.html

Place pointy end of wire, I used a nail attached to alligator clip into connector, and the other end on to the chassis.

Turn your key to the on or run position

If your gauge goes past 260 then its a good gauge if not then it's bad.

 

[wesbest96]

Replacing sensors

The sensor next to the thermostat is WT3000 the sensor next to spark plug #1 is WT3025. Both are made by BWD, both are 19mm, and both need to be treated with an anti-seize agent. You can choose to drain or not drain the coolant but either way you will lose coolant.

 

[wesbest96]

With the removal of the sensors you're just going to want to put a 19mm socket with a breaker bar. Pig tails can be ripped off in order to achieve this the sensor is bad anyway!!

 

[camoburban]

Wesbest. Those two part numbers or for what years? I picked one up and it says wt3025z. Gauge still doesn't move. Wondering if I got the wrong one. I have already tested the gauge and it looks good. I have a 95 k1500 suburban with 5.7l. Thanks

 

[wesbest96]

I apologize they are for Vortec engines! so 96+
SU109 without pig tail
SU102 with pig tail
(Duralast)

 

[ernjohn]

Use a resistor of the appropriate value to see if the gauge is really off. I found my sensor was good but the gauge is off when I tested it. the resistors can be found in radio shack or other electronics stores for pocket change.

A properly functioning sensor will give the following values +/-50 Ohm

Temperature - Degrees Fahrenheit : Resistance - Ohms

210 : 185
160 : 450
100 : 1,600
70 : 3,400
40 : 7,500
20 : 13,500
0 : 25,000
-40