how to set aux fan high???

[rcfanatic]

all i did is cut resistor off then rewire back,change fuse 15amp to 30amp and now is running high at all time at low/high temp.

E36 M42 thermoswitch, turns on at 80/88c instead of 90/99c (low/high). normally you wire it so the low temp activates the high speed setting.

If he bypassed the resistor to run at high all the time, what good does the thermoswitch do?

[nando]

It still uses the thermoswitch, but it won't turn on the fan until its already overheating (90c). Unless the fan is running all the time, which is dumb.

[rcfanatic]

Sorry, I just don't see why there is a need for a temp switch at all. Why can't the fan just be wired to be on high whenever the AC is on?

[nando]

Why can't the fan just be wired to be on high whenever the AC is on?

It is wired that way. it also turns on when the thermoswitch reaches it's setpoint. lots of people use these for their main cooling fans as well. in that case the stock thermoswitch needs to replaced with the later E36 M42 version.

[rcfanatic]

Thanks

[TobyB]

Actually, Nando, it's not- the low- speed circuit's what's actuated with the A/C.

The ONLY way to get high speed is to have the temp switch kick on.

At least, that's what the ETM says, and how my 2 cars were wired...

Given where the switch is located in the rad tank, the E36 switch seems like
a good idea to me, too. If the rad top's anywhere close to engine temp,
I'd want all the fan the car had on offer...

t

[nando]

Actually, Nando, it's not- the low- speed circuit's what's actuated with the A/C.

The ONLY way to get high speed is to have the temp switch kick on.

At least, that's what the ETM says, and how my 2 cars were wired...

Given where the switch is located in the rad tank, the E36 switch seems like
a good idea to me, too. If the rad top's anywhere close to engine temp,
I'd want all the fan the car had on offer...

t

you're right, it's what I meant, and more specicially that you can wire it to come on high speed with the AC switch by bypassing the low speed entirely.

but, it's silly to rely on having to push the AC switch when all you need to do is use the thermoswitch and have it work automagically.

[mr ilia]

Is there a step by step write up as how to wire aux fan as the main fan for cooling?

[immajackuup]

It is wired that way. it also turns on when the thermoswitch reaches it's setpoint. lots of people use these for their main cooling fans as well. in that case the stock thermoswitch needs to replaced with the later E36 M42 version.

x2,here is the switch i use.

http://www.pelicanparts.com/cgi-bin/smart/more_info.cgi?pn=61-31-8-361-787-M85&catalog_description=Temperature%20Switch%20in%20Radiator%20%2880%2F88%20deg%20C%29%2C%20E36%20318i%2Fti%20M44%20%28through%202%2F97%29%2C%20318ti%20M42