2005 Mercury Grand Marquis. 198K miles. Automatic. R134a system.
A/C is blowing warm (80 degrees since last checked). I have full blowing force on both sides of the dash. There is no loss of force whatsoever when operating the vehicle.
Low and high sensors checked.
Compressor switch engages.
The blower switch works.
Compressor pressure was checked with a gauge and read 90 on both the lower and higher. It read 90 on both when engine was off AND while the engine was running.
Please advise.
If you're seeing the same pressure on high and low sides with the compressor running your compressor is toast.
@chucktobias What I figured. Thanks for the confirmation! - When I install a new compressor, should I be replacing anything else?
You need to replace practically everything else due to likely contamination by the failed compressor. The condenser, drier, expansion valve or orifice tube need to be replaced. The rest of the system needs to be flushed out. You'll probably find that the new compressor's warranty requires this to be done. This might also be a good time to replace those 20-year-old hoses.
@chucktobias, what brands and kits are the best to purchase? I heard that 4 Seasons' compressors are a no-go thanks to Mexico.
Hard to say what brands are decent with replacement parts these days frequently being of poor quality. I would agree with @imperator that if you are not familiar with working on air conditioning the project is best left to a professional.
When I install a new compressor
I recommend you let an AC shop do the work. There is a lot to bork up if you don't know what you're doing, and it will just end up costing you more in the end.
@imperator, I would assume that will be expensive? -- Non-professionals are advising me to only repair the compressor to save time and money. LOL
Correction: Mileage is 106K
P.S. - Fans come on when the A/C is turned on.