View Full Version : temp sensors

04-07-2003, 10:03 AM
i have found a third sensor that has is located on a hose on the upper part of the engine and goes inside in the heater core...its just underneeth the air intake tube right about in the middle. i have changed a big sensor in the front, and a smaller one in the front too, and my temp sensor in my dash still goes back and forth from cold to hot. do u guys think this 3rd sensor has to do with it. im going to change it cause this is very anoying.

04-07-2003, 11:28 AM
It sounds to me like you have some air in your system that needs to be purged. That would cause the gauge to fluctuate as you described.

04-07-2003, 11:42 AM
The single wire sensor by the upper rad hose/t-stat controls the gauge and the gauge only. I'm not totally sure what the one in the line is for, but I know the EEC has settings for 'temp1' and 'temp2' when controlling the fan. Maybe that is 'temp2' that is referenced in the EEC.

04-07-2003, 04:33 PM
how do i get the air out of my system...im thinking of flushing the coolant before summer starts...and how do i do it properly...so far the gauge will stay at the farthers cold position like a car is off...then all of a sudden it moves across to hot...and mean while u hear the fan kick on..then the gauge drops down to the normal engine temp and fan turns off....is this all caused by air? sometimes i hear like bubbles flowing through the engine compartment from inside...it sounds like a waterfall from under the dash...is this air?

04-07-2003, 04:46 PM
That's a pretty good description of air in your system.

There's a link called: Cooling System Draining/Filling/Bleeding Procedure in this link

TCCOA tech articles (http://www.tccoa.com/articles/misc/index.html#)

Basically the way I purge the system is by removing the small bolt/vent/plug (it should be the highest point of the system), then pouring antifreeze/water into there with a funnel. There are other methods which will work even better, but I find that to remove most of the air.

Anyone who has a better method, please post.


04-08-2003, 06:19 PM
anyone know the part # for the temp senor...i found it, but need the #. thans

04-08-2003, 06:27 PM
My car did the same thing,try grounding out your connector.the one that goes to your thermostat housing temp sensor.If u grond out the wire your temp gauge should climb.Just clean the temp sensor and the inside of the connector that goes over the temp sensor.That fixed mine!

Rob Noth
04-08-2003, 06:38 PM
The third sensor on the heater hose under the air intake tube is the Cold Engine Lockout Switch. It's part of the electronic climate control.

Dale Puumala
04-08-2003, 06:54 PM
Oh! So when you have your fan set to "auto", that's the sensor that tells the fan to up the speed, once the engine coolant starts getting warmer.