a/c electric fan questions.

[LowR3V'in]

I have an aftermarket fan that is turned on by the a/c control through the stock wiring.


Worked well, but it shorted and smoked the wires at the fuse box.
The short was at the "normal speed relay" so that's usless now.

Instead of taking the harness apart and running new wires.
Does the a/c switch still work using the "hi speed relay".


I remember there were 3 wires at the fan.

Anyway I'd like to use the "hi speed relay" and just switch a wire on the fan if possible.
Or hook up my own relay and hook it up to the a/c as the switch and control it with megasquirt.





This was a the "normal speed relay" that was used to turn the fan on.
Seems to be a fuse there. Didn't work out though. The wires were fried.
Still can make it work, but seems unsafe now.

A/c fan relay. by jet jones, on Flickr

[vpilarrt]

That's not a fuse, it's a diode to prevent the AC form being turned on when the temp switch in the radiator gets hot enough to turn the aux fan on (at low speed).

See page 6454-0 in http://wedophones.com/Manuals/BMW/19...g%20Manual.pdf

[LowR3V'in]

I see it.
Looks like I can not just use the "high speed" relay instead without having the "normal speed" hooked up.
I'm terrible at wiring but looks like high, jumps onto normal. for the ground.

[LowR3V'in]

just for future people reading
i did get the high speed relay working just by using the radiator sensor wires
and switching using the red wire for power instead of the normal speed one.

For now it's ok. Wires to the fan seem to be a 12g.