1987 E23, several issues, starting with this one. When I have the blower motor on, no matter what temp setting or fan speed control setting, there is heat blowing out. I have manually vacced the heat control valve, it is working. If I have the blower thumb wheel on at all, the vacuum is lost to the heat control valve, and it's hot air. Same thing with the fresh air control. If I have the push button set to recirc, it closes the fresh air flap, but if I turn the blower on, it opens the fresh air flap. I checked voltage to the vacuum selenoids, and sure enough I lose voltage to those selenoids if the blower is on any setting, including defrost. Turn the blower thumbwheel to off, and voltage returns to freshair AND heater control selenoid, and they operate fine.

Other issues just for info, engine starts fine if cold, does not start at all when warm. Always idles rough. vacuum pump runs about 1 minute when the key is turned on, then shuts off and holds vacuum.

So basically, voltage to the 2 selenoids described above is lost if the blower motor is on via thumbwheel. The temp thumbwheel has no effect in this situation.

Thanks for any tips on what to try, or test.