coolant temp switch

[Arde]

I do not see the electrical fan or a temperature switch in the electrical diagrams on this site. I do have an electrical backup fan in front of the radiator but unlike the E24 there is no temp switch in the radiator. I have the radiator out and want to test that circuit before putting things back.

 

[gwittman]

As far as I know, that fan is only part of the A/C. It only comes on when the A/C is turned on and when the compressor is engaged.

 

[Arde]

The thing is the car never had AC, and I know it the fan came on once a few years back on a hot day. I will check the AC diagrams (from David V.) and see if it shows where the switch is.

 

[DougE]

Radiator Fan

I just read your post today 10/11/08 I hope you will still get this. I have a late 1972 3.0cs with a/c. The factory auxiliary fan is a very poor design (no shroud the air is undirected). I wanted to improve the fan and connect it to an auxiliary fan switch also. I replaced the factory fan with a 13" Spal high performance fan, I found an unused temperature sender in the bottom of the front intake manifold. I think the sender might have been part of the emissions equipment, not all intakes have that fitting.
I used 2 relays one is fired by the a/c fan control the other by an auxiliary fan switch (92c) mounted in the intake. The fan switch I installed is used on most BMW's 1977 an later. It comes in a verity of temperature settings.

Doug

 

[Arde]

Thanks Doug. So the aux temperature switch is not really measuring water temperature (like in the E24 for example)? It is measuring engine temperature?

 

[DougE]

Temp Switch

There is coolant running through the intake, the switch is signaling off of the coolant temperature. It would be better if it was reading directly off the radiator but this is a workable option.
Doug