I searched but couldn't find the same problem. On a '94 XJ, AC and heat works but when you select defrost, the blower just shuts off. Worked normally until today. Thanks.

 

Haha the defrost is all that works on mine! I'm gonna watch this maybe I can diagnose mine as well

 

Sounds to make like you have a bad control head. There is a switch inside it that activates the AC for the defrost but if there is a short it can cause it to act like you have the system on off. I would suggest going to the JY and finding another control head.

 

Ok, thanks I'll check into that.

 

Strange because vents run by vacuum blowers electric no interconnection ?

 

There is electrical interconnection, how do you think when you go to defrost while the AC turns on. Also, why do you think that the blower shuts off when you switch the mode to off.