wrongturninwv Posted November 29, 2006 Share Posted November 29, 2006 Please explain which coolent temperature sensors do what. I know of 3 on the 95 Impreza 1.8 engine. Need to know which sensor turns on and off the main cooling fan when the engine starts to get hot ??? Also found a sensor plug on bottom of my power steering pump. What is that one for ??? thanks Quote Link to comment Share on other sites More sharing options...
porcupine73 Posted November 29, 2006 Share Posted November 29, 2006 CTS is for the temp gauge. ECTS is for the computer/ECU which controls the fans. Not sure of a third? Sensor on steering pump can be for pressure for the ECU to bump up the idle a little bit if needed or I'm not sure if there's a warning lamp for the P.S. I don t think so... Quote Link to comment Share on other sites More sharing options...
Cougar Posted November 29, 2006 Share Posted November 29, 2006 My info showed only one coolant sensor for the car. It looked like the fan are controlled by the ECU. I didn't see any type of themoswitch that is normally in the radiator. Are you sure the other sensors you saw are for coolant temperature sensing? The info also shows a pressure sensor for the power steering. First time I have heard of that. Quote Link to comment Share on other sites More sharing options...
porcupine73 Posted November 29, 2006 Share Posted November 29, 2006 Typically CTS is near water pump suction; ECTS is near block outlet to radiator. Quote Link to comment Share on other sites More sharing options...
frag Posted November 30, 2006 Share Posted November 30, 2006 On my 96 2.2 L, there are two sensors side by side under the right rear intake plenum, one for the gauge (one wire), one for the ECU (two wires). With this info the ECU controls fuel and the rad fans. On the 1.8 L engine of my 92 Loyale, there was a temp sensor on the rad itself (right side) solely for controling the rad fan. Quote Link to comment Share on other sites More sharing options...
porcupine73 Posted November 30, 2006 Share Posted November 30, 2006 I am incorrect. With those two sensors so close to each other I wonder why the temp gauge doesn't show any flucuation even when idling hot enough for the fans to come on. Quote Link to comment Share on other sites More sharing options...
frag Posted November 30, 2006 Share Posted November 30, 2006 I am incorrect. With those two sensors so close to each other I wonder why the temp gauge doesn't show any flucuation even when idling hot enough for the fans to come on. Because the gauge is not made to react to temperature changes in a linear manner. I tested that once and, IIRC, the gauge went to it's normal position at around 160° F and did'nt move until it reached near 190-200° F when the fans kick in. I did'nt disconnect the fan to push my test further (), but I presume that the gauge needle starts to rise from «normal» a little above 200° F. I think the idea is that «normal» coolant temp is over a range of degrees. Quote Link to comment Share on other sites More sharing options...
wrongturninwv Posted November 30, 2006 Author Share Posted November 30, 2006 So you are saying the sensor at the front of the engine is the one that controls the fan. I found the other sensor is under the PCV valve buried by the wiring harness. Quote Link to comment Share on other sites More sharing options...
Manarius Posted November 30, 2006 Share Posted November 30, 2006 So you are saying the sensor at the front of the engine is the one that controls the fan. I found the other sensor is under the PCV valve buried by the wiring harness. The sensor below the PCV is the Coolant Temperature sensor - used by the ECU. The Thermostat (on the front of the engine) determines if the fans come on or not. Quote Link to comment Share on other sites More sharing options...
wrongturninwv Posted December 1, 2006 Author Share Posted December 1, 2006 Thanks.... got fan working again!! Great info thanks to all you guys on this site. Quote Link to comment Share on other sites More sharing options...
Olnick Posted December 1, 2006 Share Posted December 1, 2006 Thanks.... got fan working again!! That's great! But HOW did you get it working again? Quote Link to comment Share on other sites More sharing options...
wrongturninwv Posted December 4, 2006 Author Share Posted December 4, 2006 That's great! But HOW did you get it working again? After changing CTS, (which was no fun to get at) I checked plug to fan connector, and also changed the 4 fan relays in the fuse box on inside left front fender. Relays that I knew were good from my wifes wrecked 96 Outback. Changed things all at one time cause I needed car working fast. Fans now work. Just hit and miss. I just got to get back in the habit of listening for the fans to come on and off again. I am older now and cant hear as well as I used too. I found out a long time ago on the older Subarus you cant always trust the temperature gauge inside the car. Open the hood once in a while, turn down the radio, take time to look around and listen. This will save you alot of money down the road. The computer in you car can only tell you so much,the rest to keep it running right is all up to you. Thanks again guys Quote Link to comment Share on other sites More sharing options...
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