Okay, I've spent hours going through these threads and can't find one with my problem. Both blower motors run high speed regardless of the "low, medium, high" switch setting. They do turn off. I am familiar with the Darlington transistor failure defaulting to high speed, but would both blowers be on high? Would the climate control module be suspect? In addition, the A/C clutch relay does not get 12 volts to activate. Also climate control module suspect? Or am I chasing the wrong rabbit? Any ideas before I rip into the dash would be appreciated.

 

Hi William,

Year and engine please. Not an expert but I do know that the high-side low pressure switch (on back of a/c compressor) cuts power to the clutch when refrigerant pressure is low.

 

Thank you for replying.
Yep, I realized after posting that I didn't include enough info.

1989 XJS. A/C system fully charged. I can apply 12 volts directly to compressor relay and the compressor works fine. There is no voltage coming from the climate control module to pin 85. I have tried it with the system in "manual: as well as "automatic." Still a puzzle why both blower motors operate on "high" only. I verified this by separately removing each fuse. One clue could be that the A/C relay and blowers worked properly until I removed and replaced the center console. Maybe I disturbed the mode switches. Not sure if Mr. Lucas attached the wiring securely.
Anyone else experienced this problem?