Aux Fan questions..... What do the experts say?

[western99]

I have a 95 525 ia and I had a couple of questions for you e34 aficianados out there (you know who you are....). I am stumped on this topic

1) When should the aux fan come on?
2) How can you check if you have power going to it?
3) How can I test to see if the aux fan is working properly?

I have my AC, and it is working fine, and the temp guage is always at 12, but there are times when I am at a stop, it feels like the aux fan is kicking in but I do not think that it is. The fan is 1 yr old. Fuses are all ok. What can I do to test if it is working correctly. Any advice would be appreciated.

Brian

[winfred]

it should come on low with the ac all of the time and when the pressures in the ac system gets high enough the fan kicks into high, the other time it can come on is when the sensor on the right side (cool side) tank of the radiator gets high enough the fan will come on low and if it gets hotter it will kick into high, this only happens when something is seriously wrong and you are minutes away from engine dammage if it can't regain control of coolent temp. the fan's first function is to make the ac work at low road speeds and keep pressures in check, cooling the engine is secondary

[Kalevera]

it should come on low with the ac all of the time and when the pressures in the ac system gets high enough the fan kicks into high, the other time it can come on is when the sensor on the right side (cool side) tank of the radiator gets high enough the fan will come on low and if it gets hotter it will kick into high, this only happens when something is seriously wrong and you are minutes away from engine dammage if it can't regain control of coolent temp. the fan's first function is to make the ac work at low road speeds and keep pressures in check, cooling the engine is secondary
True. The quick and easy way to test it is a) listen for it with the A/C on, b) get a jumper wire, pull the harness connector at the radiator temp switch, and jump the brown (ground) against either of the other two leads -- low and high speed. Relays should click (located in the front aux electrobox) and the fan should turn on. Use a decent gauge wire. If you've got no low speed and the relay's clicking, do a resistance check on the ballast resistor (mounted on the side of the fan, reachable through the bumper or more easily by pulling the sucker off).

More can be found in Bentley's or on Don Gale's page.

best, whit

[uscharalph]

Mine comes on with the a/c or when the temp needle hits 3/4. Thanks Whit for the info on testing it.

[western99]

I will test it and hopefully it is just me being critical of my car.

Brian