Club1320

1986.5 928s Auto.

I have a sensor on the front bottom right corner of my radiator. This would be the drivers side. There is also a harness hanging down there as well not hooked to this sensor, but right near it. I would assume using common sense the two go together. Can anyone tell me what it does? Is it a temp sensor?


Chris.

F18Rep

I'm thinking fan switch...Bruce

Mrmerlin

connect the wires to the switch its for turning on the elex fan if the coolant gets too hot

Club1320

Ok thanks. The car has duel electric fans and the p/o wired them to come on with ignition. Makes sense why that sensor is disconnected. Do you think this has anything to do with the coolant light on the dash to be on? I have heard its more common that the sensor in the expansion tank is to blame.

Dave928S

If you have a coolant warning then you should make sure you determine the cause and fix whatever the problem is .... NOW.

It might be a simple issue but it could also be serious and you'll end up cooking your engine. The PO should have left that switch connected and in circuit, unless another sensor has been installed as an alternative.

You need to connect the wires to the switch and also check your coolant level sensor, level of coolant, make sure there are no leaks and that you have circulation in the system, and that it holds pressure. You should also check that what has been added has been done correctly.

Check everything systematically and don't do any miles until you know everything is right.

Glen McCartney

Did the PO remove the electric fan in front of the AC condenser? If so, hooking up the wires to the sender won't do anything. That temp sensor in the radiator turns on that fan when temp rises. If he removed it, there will be an electrical connector where the fan was, two terminal, one terminal will have a brown wire (ground) and the other terminal will have two wires, a red and a red w/green stripe. He red wire is the wire that will turn on the fan when temp is reached. The red/green wire will turn on the fan by the temp switch located on the intake manifold, it will continue to run the fan after the car is shut down if the heat soak is high enough sensing then temp of the intake manifold.

nc_growler

Totally agree with Dave here. If your fans are wired to your ignition so that they are always running when the car is on (same as if you were running your A/C) and your car is running hot, you've got a problem that has nothing to do with this sensor.

Go investigate!

Mrmerlin

Thanks for adding this additional info it should have been posted in the first post, as it changes the diagnosis

Club1320

The original post was only to determine what the sensor was for, not a diagnosis. As for the other posts, i did check the coolant lvl, pressure and if it was flowing when i purchased the car. The car does not run hot at all, has no overheating issue, and i have no reason to believe anything is wrong at all other than the light. The p/o told me he wired the fans to come on with the ignition to keep the ac blowing cooler at idle. Wheather or not thats the actual reason is unknown, but as of now i have had no problems. Up until the most recent owner the car had a fairly extensive service records that came with it. I have contacted the p/o that did most of this work, who told me he purchased the car from a collector. He owned the car as recently as 05 and catalogued all the major service work done, along with the brand new behr radiator that was installed, also timing belt, water pump, transmission service etc. Mechanically the car is fairly sound. Again thanks for all the help and im sure i will have many questions to come.