I have a factory service manual for our 2008 PT Cruiser. The PT has a relief valve that blows refrigerant if over pressurized. Here is the issue, in my view. Page 260, section 7-24 of the service manual lists fan control logic. It says with AC on you will ONLY get fan action with coolant temp above 180F. So if you go to a hot parked car, windows up (cold engine), start it and turn on AC you WON'T get fan and you will over pressurize the refrigerant. Should I try to jury rig the wiring or live with this problem?
Don't understand why they designed this fan logic! Or, what am I missing?
I have to respectfully disagree with your manual.
When you turn the AC on, the fan should run at low speed.
It sounds like your low speed isn't working.
It's easy enough to test. Unplug the connector at the fan. With the AC ON (on the harness side of the connector) you should have power to terminal 1 if the low speed relay is good and there's no problem with the power and the computer ground to the relay.
If you don't have power there, test the low speed relay.
If you do have power there but the fan doesn't spin on low speed, replace the fan.
You can also test the low speed function of the fan by jumping power and ground to the "fan side" of the connector. Here, terminal 1 will be on the left, ground in the center, terminal 3 on the right.
