a/c blows hot air on 1999 Mercury Grand Marquis

a/c blows hot air. i found that diconnecting the climate control module for a few seconds sometimes makes everything work normally. i have to do this frequently and it doesnt always work. i want to fix it for good! please help.

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5 answers
This fix is great.

Set air temp between 40 and 90 degrees.
.
Turn off climate control with off button.

Hit off and floor at the same time.

It will enter into self test.

You will see a spinning wheel on the display.

let it go through the test.

Good Luck,
i have a ford tauras that does that sometimes try disconnecting the neg. battery cable for like 15 minutes then reconnecting. works for it
DO NOT ADD FREON TO YOUR SYSTEM UNLESS YOU CHECK THE COMPRESSOR HEAD PRESSURES FIRST - unlike the suggestion below.

I see several people a week that overcharge their systems with AC Pro or similar systems.
Always check with gauges... if empty, pull system in a vacuum first. Repair any leaks.


"Your A/C needs recharging. An amateur can to it by themself by getting a recharging kit from a part store for like $30. If you take it to a mechanic, they'll charge you at least $100. But when you're A/C won't blow cold air anymore, it needs recharging. - amadhatter53"
Your A/C needs recharging. An amateur can to it by themself by getting a recharging kit from a part store for like $30. If you take it to a mechanic, they'll charge you at least $100.

But when you're A/C won't blow cold air anymore, it needs recharging.
Disconnecting things is not a good way to determine what is wrong, it doesn't give any real clues as to what might be bad. You'll need to see if the compressor is getting power when the A/C is not cooling, if it isn't then the electrical circuit to the compressor needs to be fault traced to find the problem.
These systems are fairly complex so I advise taking it to a professional.