11-12-10, 04:39 PM
I've got a '02 Seville SLS with a really weird A/C problem. I had no problem with it. Had it set at 72 degrees. Left the car for about 2 hours, got back in, drove off and it got really cold...like 60 degrees while set at 72. Now I have to have it set at 80 or above to get any heat, on either side, then as I drive down the road, maybe 10-15 minutes later it might go cold, it might stay hot. If it goes cold I can shut it off for at least 2 minutes and it'll will go back to hot then slowly go cold again like as if it had a bad vacum line, but it has no vacum.
11-13-10, 05:08 PM
Pull your Diagnostic Trouble Codes from the car's built in code reader/scanner system. The sticky thread "How to pull codes". Study it well, then practice. Return to the thread and open the link for your car year which leads to the page with a Master Index - click on the blue lines to get to definition lists of P,B,C, and U codes.
You may find either an air blend actuator fault or............
Just to the left of the steering column, in the face of the dash panel, is a small square grille. This leads to an air tunnel to the cabin air temperature sensor - the "aspirator". A small computer muffin fan pulls air into the grille.
Turn the key ON and set the HVAC to some normal heat mode, with the A/C button OFF. Listen carefully at the grille. Fan running ??? If so, now take a paper clip bent into a small hook and ease the grille out of the dash - careful - there's a small thermistor bead just inside. Blow down and through the tunnel with a can of pressurized computer cleaner air - you will probably see dust and fuzz fall on the floor. Leave the grille out and go for a drive - all OK ??? If the fan is NOT running or the air cleaning didn't do the trick, the module may need replacement or the fan needs lubrication.
To remove the module (dealer item only) stick your finger in the rubber air duct grommet for the side window - the grommet in the end of the dash panel at the door.....and yank the end of the dash off. Remove the plastic air pipe. Look straight in and find a 1/4" hex head screw. Remove it with a magnetic socket and extension. Fish out the module and connector - unplug it. On the board is the muffin fan. Remove the seal tag over the blade hub. There should be an E-clip which holds the blades onto the axle - put a drop of synthetic engine oil on the axle and spin/free up the fan. Test the fan by applying 12VDC to the fan leads. If it's OK, put it all back together using magic words and a scotch and water.