I think the aux pump should stay off unless you have the heat on, and your temp wheel is set low, and the next to right button, EC is pushed in, that way the AC won't come on either. The temp sensor is either that small square grill on dash, or if you don't have that, it is located under passenger speaker. There is a hose going to the one on the dash, anyway, one section is made of foam that has a tendency to deteriorate. Think you have to pull glove box, but feel around behind if you can first.

__________________
83 SD

84 CD