If you are not getting voltage to the heater control valve (with the A/C on), I'm afraid I can't help you, never had to investigate beyond the above. You should consider getting a Bentley manual if you intend to keep the car for a while, you'll use it.

I have a 85 535i which I bought used with about 200k on it. My question has to do with the hvac system. It feels like the heat is on all the time. Even when the a/c is on i can feel heat coming from under the dash. Also the sliding vent controls dont work. The a/c comes out of the main dash vents in the middle, never from the defrost or floor vents. i'm in the Navy stationed in Puerto Rico so needless to say its very hot here all the time. i'm transfering back to the states in may so I want to fix it right so I can have heat and defrost when I need it. BTW my 85 seems to be somewhat odd. It was a european delivery car. It has head rests in back, no "535i" emblem in back and the fuse box has those old fashioned german fuses instead of the normal ones. Any insight would be appreciated.

-Mike