Need help debugging my AC problem...

[jacktahoe]

My AC has been intermittent now for about 2 months.

When it works it works great. Every once in a while the light blinks on the AC switch indicating something is wrong. I usually wait a few miles hit it again and it works.

Last time, I had a 100 mile trip and it would not turn on at the beginning, then about 90 miles in it turned on. It ran for a few more weeks (about 500 miles of driving) and then does not work now (blinking light).

Since when it turns on it is cool. When it is 110 outside and is working it is plenty cool inside, I assume that the compressor is working fine and it has enough Freon in it.

It sounds like an electrical issue somewhere to me....

How do I figure out what is wrong ?

Oh it is a 2004 Limited with a V8, 200K miles.

Jack

 

[djkurious]

The same thing happened to me until I replaced the relay under-hood fuse panel. Been perfect ever since. It was labeled "magnetic clutch"

 

[keakar]

there is a crank sensor that turns the a/c off if the engine crankshaft at the a/c crankshafts are not turning at the same predetermined rpms. it tells the computer "something" is wrong with the a/c so it shuts the compressor off and the light blinks to tell you "something" is wrong.

sometimes its just a slipping belt or bad clutch slipping, sometimes its not getting good voltage from a bad relay ant that lets the clutch slip, but sometimes its the sensor inside the compressor that goes bad.

if its the sensor inside the compressor then the only way to fix that sensor is to install a new a/c compressor.

I would try putting in a new relay like djkurious did and hope that that is all it is

 

[jacktahoe]

Not the relay

I changed out the relay and it still fails

and it is 105 here today