Strange A/C problem

[Road Rash]

While the search function is down, maybe someone can help diagnose my A/C problem. (I did check the last 30 pgs with no luck)

'99 540i/6: Occasionally, the A/C will quit working. When it happens, the blower will be on very low and blow only ambient air. Pressing the a/c button, or changing the blower speed will have no effect. Even if I turn the unit completely off, the fan will still blow out air at low speed. But, if I let it sit overnight or even a few hours it will start working like normal. I can't confirm, but it seems to be temp. related. Usually happens when it sits out in the sun for a while. :confused

Any suggestions where to look. Recharge freon, resistor, . . .:help

[fuddyduddy121]

Your problem is not clear, is it the A/C compressor (air temperature) or is it the level of the fan, or air volume? Do you still have the same problem if the heat is on?

[phoenix530]

Don't know too much about this stuff, but I do know that in some vehicles if the temp raises too high then the first thing to shut down is the AC compressor. This is to aleviate some of the strain on the motor and help it run a little cooler.

I would first check to see if you have enough coolant in the radiator. Then check the engine temp and see if it's at normal operating temp. Then perhaps somehow check to see if your A/C is fully charged.