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AC Electrical Problem

My AC clutch will not engage until the engine gets hot enough to call for the radiator cooling fan to switch on, which in moderate weather at highway speeds can be forever. (Single electric cooling fan.) Of course, the AC should override the engine coolant sensors and turn on the fan and engage the clutch. Once the engine is hot, the AC works normally. No one seems to know where to start looking. It’s an '03 Grand Marquis with an interceptor engine package.

I’m probably going to be little or no help here but does this car have EATC? (electronic air temperature control)

If it does, perform this test and see if anything pops up. That’s a starting point at least.

Yes, it does! I’ll do this test today. I am concerned that a problem somewhere could actually cause the engine to overheat. Thanks.

I ran the test; it showed everything as ‘888’ normal. Very frustrating…

When was the last time you had you A/C serviced? The 134a oil in the cooling system needs to be at a certain pressure to have the compressor start. If it is low the compressor won’t start. It comes on once the engine is hot because the engine heat causes the coolant to expand to the point that the compressor kicks in. You can opt to have a full service (probably +$100) or get a can of 134a oil from an autoparts store. Get one with a guage on it and follow the instructions. Please Note; that 134a oil is an EPA item and needs to be disposed of properly. Refilling is fine but replacing needs to be done by a pro.

The symptons you are experiencing are not an indication that your AC system is low on oil. Do not add oil to your AC system. In an automotive AC system the oil and the refridgerant are mixed, there is not a seperate pressure reading for the AC oil and for the refridgerant. Bad advice in regards to automotive AC systems is much,much worse than no advice.