I recently purchased a sweet used 98 740I and have some questions. The temp. controls on the passenger side seem to work fine, but on the drivers side when it is set to auto, I get full heat from the floor and defroster. When I have it set to the dash vents, I get cool air from the driver vents, even when the temp is set to 75+. The passenger side works like it should. Also, the air conditioner compressor will not kick on. Any thoughts form you experts??

Thanks

some things to check or reveal before we start tossing out info:

1. what is the ambient temperature? Is it below 42 degrees (F)?
2. are you familiar with the stratified air temp controller for the dash vents?

Check the Climate Control Chapter in your owners manual if the above is unfamiliar to you. If you don't have an owners manual..you can download one in PDF format...they are located at www.e38.org ...look at the bottom of the left column...if your model year isn't listed, download the one closest to your model year...there's not that much difference between model years that can't be extrapolated to yours. :)

Thanks for quick reply. Answers:
1. Temp today was 58 outside.
2. Read the manual, and yes I was aware of this.

Yesterday the outside temp was 75 deg. and still have the problem. I cannot hear the a/c compressor trying to kick in. Could it be a bad control unit?

Yesterday the outside temp was 75 deg. and still have the problem. I cannot hear the a/c compressor trying to kick in. Could it be a bad control unit?

Or system is low on freon. That way the low pressure cut-out switch will not allow the comp to engage. Put a refrigeration gauge on th esystem. It will tell you a lot.

Anyone else have any thoughts on this. I am getting cool air from the drivers side vents with the temp. set a 80 dg. The passenger side works as it should. I am hoping to fix this myself. My closest dealer is 85 miles away.