JWXTREME

I woke up to a completely dead battery last week. I couldn't figure out what caused it because everything was turned off. It rained hard for a couple of days and I had the defrost on when I turned the car off. When I started it, I didn't have control of the blower through the switch. It was running on high, with the switch turned off. It runs all the time even when I turn the car off. The only way I can get it to shut off is disconnect the battery. It will eventually stop on it's own after a couple of days and return to normal. I can then use the controls and they operate perfectly. I've been keeping everything turned off when this happens and it will eventually start blowing again with the switch turned off. I have the basic **** style switches (no digital climate control). I think it's something electrical as always with these cars. I tried checking all of the fuses but can't find the fuse to even shut it off. I'm about to drive it off of a cliff. Any help in troubleshooting this is much appreciated! Thanks!

87SAM

Any codes? Maybe a bad relay??? here is a schematic

JWXTREME

Thanks for the schematic, I'm sure it will come in handy!

I pulled the codes and this is what I have:

U1096H

U1064H

U1016H

I'm going to look them up now.

JWXTREME

U1096H = Loss of Communications with IPC

U1064H = Lost Communications with BCM

U1016H= Loss of Communications with PCM

I know these are all history codes which I reset, and things seem to be ok for now. Any suggestions on troubleshooting if the problem continues??

Bill Curlee

HVAC heater blower troubleshooting all depends on if you have MANUAL Controls or DUEL CLIMATE CONTROLS. The schematic provided is for manual fan speed controls. If you have Duel Climate, there another schematic that you need. I am not that fortunate as to have the schematics electronically but if someone does, its in Vol1 of 3 on page 1-219 in the 2002 C5 service manual.

The duel Climate control center outputs a digital signal to the Blower Motor Control Processor which in your case is most likely defective.

Which type of HVAC controls do you have???????

BC

JWXTREME

Bill,

I have the manual controls. Any help is appreciated.

I reset the codes and it went back to normal for the weekend, and then this morninig it started blowing again on it's own.

I'm now getting code C1255