climate control issues

[pgerald]

Hi I have a 84 633, the variable speed control on the fan only works on high or off, plus the temp control is either hot or cold???

also my idleing has been acting up, it doesn't sit even at 750 plus sometimes it sticks at 2000 and you have to kick it down, would appreciate any help, thanks

[KC Ron Carter]

Lots of issues: The fan first:


The heater fan only having high or nothing is a the NPN transistor on the back of the blower control (NOT the one that is on the blower transistor pack next to motor itself. If you look at the schematic, the motors get their power through this NPN transistor unless the control switch is in the maximum position in which case the transitor is bypassed.

http://normgrills.net/bcg/Heat_%26_A...#anchor1090602

[KC Ron Carter]

My WAG is the vacuum line to the temperature sensor on the panel under the drivers side panel.

[KC Ron Carter]

Most issues of idle on BMW are vacuum leaks.