Hello,

Where are the coolant sensors located? (radiator fan sensor? ,temp gauge, some others?)85GT.
Could somebody tell me the name, and locations for these sensors?
The problem is that first I had a working gauge, the radiator was sometimes on and sometimes not when it should be since the spring when I bought it, so that never really worked.
But now the gauge wont read the temperature anymore, its still pegs when I start the car and my thermostat is also good.
My very "helpfull" Haynes says nothing about it...

Greetings,

Mark

85 GT 3.1L

Ok,
The temperature sensor that goes to the guage in your car is in front of #5 cylinder (left side of block as you face engine), it's screwed right into the block just to the left of the spark plug.

Unplug it, ground each wire individually...one should make the guage peg and the other should turn on the coolant light. If this works, I'd say the sensor is bad or needs to be cleaned up. Unscrew it, clean the threads and the hole it was in, put it back in with NO sealing tape of any kind cause it has to ground to the block. Plug it back in and see if all works well (clean up the connections in the plug also).

If you buy another one, make sure it's the one that sends to the guage, NOT the ECM (there are 2 coolant sensors). If you don't specify this, most autopart stores will give you the wrong one. You can usually get them for around $20.

The fan switch (turns on the radiator) is in front of the thermostat housing and has a single wire going to it.

The other coolant sensor is in the thermostat housing area also.I think it's close to the fan switch (in front of it)...but has 2 wires to it I think. This sensor goes to the ECM.

Dave

Thanks Dave for the very clear description! + for you.

quote Originally posted by ditch: Ok, The temperature sensor that goes to the guage in your car is in front of #5 cylinder (left side of block as you face engine), it's screwed right into the block just to the left of the spark plug.

i think it actually screws in to the head

Left to right, ECM temp sensor, fan switch, cold start injector switch:

and guage sender/warning light switch:

JazzMan

Thanks Jazzman for the pictures!

Could somebody give me the GM/Delco part# for the guage sender/warning light sensor?

would a disconnected coolent sensor cause a no start situation?? Just curious.

quote Originally posted by FieroFanaticFromHolland: Could somebody give me the GM/Delco part# for the guage sender/warning light sensor?

The original part number is 25036809, though it may be superceded by now. No worries, if it has been superceded the dealer will be able to get the new part number with the old number to start with.

JazzMan