Hey guys, any help would be appreciated.

Bought a 1991 Charade 1.0 CX a few days ago. First it overheated, and we discovered that radiator and hose were leaking so we replaced them. Now the fan does not come on with new radiator, so we bought new thermo switch (have yet to install.)

We were driving around with the heater on, which kept the engine temperature low; but when we were stopped in traffic, the car idled very low and at one point stalled (and was difficult to revive at first.) The car idles fine without heater, but with heater on the revs shoot right down and things get pretty rough.

Any tips?

-Philip