no check engine light that i noticed but i will check for codes next time i get a chance. Didn't get a chance before i had to leave to find out how to check the coolant temp sensor. Figured it was a simple on or off kinda switch switch so i tried it unplugged and with a jumper wire in the plug and neither of those seemed to make a difference. But if its not just on or off that could be it. I need to find a fsm to figure out what wire it is at the computer so i can trace it to make sure it didn't rub through and ground out somewhere.
Your CTS (on the thermostat housing) is probably okay. As well as providing a voltage input to the PCM to control the cooling fan relay, it also provides this voltage to the PCM for it to control injector pulse width and ignition timing. If you haven't had engine performance problems you can be assued the CTS is working properly. The CTS is a variable resister that is inversely proportional to temperature, i.e., when the coolant temperature is high the resistance is low and when the coolant temperature is low the resistance is high. Disconnecting the ECT harness connector would be like introducing an infinate (high) resistance and the PCM would see zero volts, shorting (jumpering) the connector pins would introduce a very low resistance and the PCM would see a high voltage input = High Coolant Temp.
The PCM provides a
ground to the Fan Relay control coil when it determines the coolant temp is too high or A/C is requested. If you removed the A/C low pressure switch, the PCM won't receive the A/C request signal. The ECT is probaly okay.
If the Fan Relay energizes any time the ignition switch is in the RUN position (you feel it click), there's probably a short to ground in the wire that controls the relay coil from the Fan Relay socket to the PCM....or, the fan power contacts in the relay are welded closed (power to the fan, regardless of the relay coil opening or closing).
First, you should check the relay. Remove it from the PDC. Look at the pin side of the relay. If the pins are numbered 1, 2, 3, 4, and 5, use an Ohmmeter to check for continuity between pins 2 and 4 - there should be high to infinite resistance (contacts open), if you read continuity (near zero resistance) the power contacts are welded closed - replace the relay. [*If your relay pins are numbered 30, 85, 86., 87, 87A, read between pins 87 and 87A]
A quick check of the relay is to swap the Fan Relay with the Starter Relay and see if it works okay.
If the relay checks okay, check for a short to ground in the relay control coil wire from the relay socket (not the relay) to the PCM. Disconnect the negative battery cable. Using an Ohmmeter check for continuity between pin 5 [*85] socket to chassis ground. You should see an open (high to infinate resistance). If there is continuity in this wire to ground disconnect the PCM harness connector and check the wire again. If there is still continuity to ground in this wire it's shorted to ground somewhere and needs to be repaired. If you read an open in this wire the PCM may be defective, providing a ground internally.
