Blower motor intermittent.

The blower motor on my 2000 Impala is intermittent. When its not working I have no power at all to the motor not even in the highest position which bypasses the resistors. I have checked the ground wire to the motor when its not working and the ground is good. When the blower is working it works great at all speeds but when its not working there is no sign of life at all with no power at the blower, not even brief operation as if a wire was loose. Also one time the car was shut off with the A/C running and when I started the car again the A/C light on the switch was illuminated even though the fan switch was off. When I started the car and turned on the fan it wouldnt run but the A/C compressor engadged. At this point I couldnt turn the A/C switch off, the light remained on at all times and the fan wouldnt run, even with fan selected off the A/C switchlight remained on but the compressor would disengadge. With this I dont think there is a problem with the blower, fan switch or the resistor, is there a relay or computer logic that controls the fan and A/C compressor logic?

Did you ever get this resolved? Did you happen to notice if the display above the rear view mirror was out at the same time as the blower not working? I'm having a similar issue, and suspecting the BCM.

It is pretty common for the Blower Motor Relay to fry in these cars.
It is located between the blower motor and the firewall, take it out for inspection before you go get a new one, there are 2 kinds and seems to be no method as to which one will be in there.

Would a blower relay cause the upper console to not light up and cruise control to cut out sometimes?

In my case the only thing affected was the blower motor. I recall during my research that others have had random elecrical problems "clear up" when replacing the BMR. i was scouring google for solutions at the time so i could be associating damn near anything with the BMR.

since blower is part of the problem, and the blower motor relay is a known issue in these cars, this is where i would start my diagnosis.

to supplement. both Your issues may also be in the control unit for the AC, since this is wired with the dash lights. I believe there are also 2 different versions of these, a 3 plug, and a single plug.. go figure..

I ended up getting mine resolved. Bad ignition switch
http://www.automotiveforums.com/vbulletin/showpost.php?p=6814694&postcount=5

i got the same problem it works when it wants to no other electrical probs minus the rear defrost but the blower motor is the main prob in keeping my windshield clear(minnesota winter)

I had a similar problem with my blower not working. After a significant amount of troubleshooting - I had the same culprit - the ignition switch.

This was replaced and haven't had a problem since.