Ducman82

any one know what temp the Aux cooling fan comes on on an OB? i know when the AC switch is on it runs, but i can't seem to find anything on it in the WSM or owners manual.

4drgl

My 80 kicks on when the temp gauge hits half or a bit above. Usually takes about 20-30 minutes of idling in the garage. (unable to drive yet!)... I know that doesn't help with specific temp but...

smiffypr

95 degrees C (at the bottom of the radiator) according to the service info technik document.
On my '80 it comes on when the gauge is about 2/3 of full scale, well before the red segment.

R.Pires

Hi,

Sorry to ressurect this old thread, but is there a way to test if the aux electric fan is working, other than leaving the car idling in hot weather waiting for it to trigger?
It's getting hot in here, and in traffic my car almost reaches the last white line, but neither when working nor after shut the car and leaving the key in position 2 it doesn't come on.
Maybe the engine it's not hot enough to trigger it, but I would be more calm if I could test it and know the switch on the radiatoir is ok!
TIA for you helps.

Regards

smiffypr

If you either remove the fan belt, or put a piece of cardboard in front of the radiator, and let the car idle, the temperature will start to rise. The fan should come on before the temperature gauge hits the red section. The thing to keep a close eye on is the overflow pipe from the neck of the header tank. If steam starts to come out of there and the fan has still not come on that is the time to turn the engine off or remove the cardboard.

Mrmerlin

To test the fan remove the connector for the fan and connect 12V see if it comes on.

Also look to see if the fan was rubbing on any parts of the harness and has cut the wires

NOTE the switch for the fan is on the bottom front of the radiator , sort of under the headlamp motor.
see if the wires are plugged in.

if so touch them together the fan should come on with the key in the run position,
if this happens then the switch may be bad,

I have replaced a few of these switches.

If the fan doesnt come on when touching the wires together then check the fuses.

NOTE to test the fan switch remove from the radiator after you drain it,
then use a continuity tester, and heat the switch with a heat gun ,
see if it will close, and with the IR gun see what the temp of closing is ,

NOTE your radiator may also be plugged at the bottom thus reducing the flow,
and possibly causing the switch to not see the hot coolant,
though not a very likely scenario

R.Pires

Thanks Mrmerlin for the very detailed explanation.
Just one more question, IF last time my mechanic worked in the car the wires were accidentally connected in reverse, will the fan work all the time or won't work at all?
Thanks

smiffypr

The switch is a switch. It doesn't matter which way around the wires are connected.

Mrmerlin

what smiffypr said

jpitman2

If you pull the rubber boot off the fan switch so you can see the connections, you can easily short them with a screwdriver to test the relay, fuse and fan. It could also be a failed relay on the main board, or just the fuse for the fan. After a hot run in mine one day I happened to check the fan relay (original unit based on the markings) and it was too hot to hold, so it might be useful to replace it if its old. I have found that the temp gauge does not track very well with the fan coming on (fitted a led across the relay so I know when its on) with the fan switch at the bottom of the radiator - fan switch at bottom, gauge sender up on top of engine.
jp 83 Euro S AT 55k