My 2006 Chevy Express 3500 V8 Gas Passenger Van has rear fan, temperature and up/down outlet dial controls in front and on ceiling of 2nd seat. The fan only operates in high (no resistance?) from both controls after originally operating in all 3 positions. I have located an AC Delco part 158623 that bills itself as "RESISTOR,AUX BLO MOT 2 WHEEL DRIVE". I would like to know where this resistor is located so that I can troubleshoot the resistor and wiring.

 

Have you been able to locate the resistor? I too have this issue with my 07.

 

In express cargo van at the junkyard: mounted on forward side of blower motor housing on left wall near rear of vehicle. Understand that in a passenger van it is somewhere under the left side panels. Someday I'll get all of the stuff out of the removed rear seat area and have a look. Lived without it for over a year. I got the part from the junkyard cargo van to try.