Does the coolant temp. sensor mounted by the thermostat on a 94 cavalier with a 2.2 liter engine control when the electric fan comes on? The sensor has 3 wires. A guy at O'Reilly Auto Parts told me this sensor is just for the temp gauge, and there was another sensor for the fan, but I only can find the one sensor by the thermostat.
Thanks for any help.

Yes guy at O'Reilly Auto Parts, Is right, The fan has a relay switch if you fallow the wire from the fan you will see a box looking thing, with wiring harness coming out of it.

Sounds good, the reason I wanted to know this is because I am going to put a mechanical water temp gauge, and mechanical oil pressure gauge in. The oil pressure gauge is no problem, but I will need to remove the factory electric coolant temp. sensor to run the mechanical gauge.
Thanks for the help.

The Engine Coolant Temperature Sensor and Temperature Gauge sender is contained in the one screw in unit by the Thermostat---should have three wires connected to it (As you say yours has)

3.1 Vin T's are wired differently and QUOTE[and there was another sensor for the fan] applies.

This info is from my1993 2.2 shop manual, sounds as though it still applies to 1994's.

2.2's have:-

1. One YELLOW wire (+5 volts from ECM) and

2. One BLACK wire to sensor ground at ECM.

This input is used by the ECM to control the Radiator Cooling Fan and other things!

3. One DARK GREEN/WHITE wire (To one operating coil of the Temp Gauge, grounded return through the case) THIS is the circuit which operates the temperature gauge.

If you remove this OEM sensor/sender you will utterly confuse the ECM as it will have no Engine Coolant Temperature Sensor information!

You will need to find another method to install your mechanical temp gauge---not sure if a "T" would work here.


Hope this helps


Alnot

Kevin Holt wrote:Does the coolant temp. sensor mounted by the thermostat on a 94 cavalier with a 2.2 liter engine control when the electric fan comes on? The sensor has 3 wires. A guy at O'Reilly Auto Parts told me this sensor is just for the temp gauge, and there was another sensor for the fan, but I only can find the one sensor by the thermostat.
Thanks for any help.

There are various coolant sensors that could be used on your car.

None have 3 wires.

The sensor for the PCM is definitely installed. As posted before, it has 2 wires and one is black and the other is yellow. It is most likely in the head near the thermostat.
Never ever modify or remove this sensor.

Your car may have a gauge sender (but the PCM could also be providing the info for the gauge).
If it does it will be a single wire sensor with a green wire (probably with the stripe of some other color). This sensor would not be critical to the car if changed or removed. This sensor may be located anywhere on the engine but is most likely on or near the T-stat housing.

Your car may also have a mechanical switch for the fan (but its far more likely the PCM controls this and its not used). This would also be a single wire sensor with a green wire (probably with the stripe of some other color). If this is installed, removing or moving it will affect the cooling fan operation.

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This is kind of what I was thinking, I know the fan relay is what gives the electric fan the 12 v current to run, but has nothing to do with what temp. of the coolant that switches the fan on, this is controled by the coolant temp. sensor.
Like I said earlier I only have the one 3 wire temp. sensor. So I guess I will have to find another location to install the mechanical temp gauge. Maby I can drill and tap a new hole in the thermostat housing, right beside the factory temp. sensor, it looks like there is enough room to do this.
Man, they don't make anything easy on these computer controled cars do they??
Thanks for all the help guys.

Quote [There are various coolant sensors that could be used on your car.

None have 3 wires.]


I have two with three wires in both of my '93 Cavs that operate as I posted before.

Maybe this '94 still has the '93 system and it was changed in later models

This is just to keep the record straight for those with three wire sensors


Alont