The cooling fan never comes on by itself. It does operate if the temperature sender is disconnected.

Here's what I've done so far:
1. Replaced the temperature sender. (And tested the resistance of the sender when cool/hot.)
2. Tested the relays (cooling fan and A/C fan relays).
3. Tested for continuity of the temperature sender yellow wire between the sender and the computer.
4. Tested continuity of the temp sender connector plug.

What am I missing?

Scan the PCM to see what the CTS is reporting to it. If the PCM thinks the coolant is below 233ºF, the fan will not turn on. Also, if the PCM thinks the vehicle speed is over 34 MPH, the fan will not turn on.

Does the fan turn on when the air conditioning compressor is on?

The cooling fan never comes on by itself. It does operate if the temperature sender is disconnected.

Here's what I've done so far:
1. Replaced the temperature sender. (And tested the resistance of the sender when cool/hot.)
2. Tested the relays (cooling fan and A/C fan relays).
3. Tested for continuity of the temperature sender yellow wire between the sender and the computer.
4. Tested continuity of the temp sender connector plug.

What am I missing?
check PCM connector C1 pins 11 and 10 they ground the fan relay coils that turn on the fans. with a/c on pin11 dark green should be ground.this is primary fan relay coil ground...

check PCM connector C1 pins 11 and 10 they ground the fan relay coils that turn on the fans. with a/c on pin11 dark green should be ground.this is primary fan relay coil ground...




IF YOU DO NOT HAVE SUFFICENT A/C FREON CHARGE THE FAN WILL NOT COME ON WHEN A/C IS TURNED ON. ALSO FAN WILL COME ON ONLY IF ENGINE TEMP IS 235DEG F EVEN IF YOU HAVE NO FREON. BY REMOVING ECT CONNECTOR PCM IS OPERATING IN FAIL MODE AND FAN IS FORCED ON AS PROTECTION.......