electric fan running at cold start

[DownUnder]

Went out tonight, after the Rover had been sitting about 12 hrs, and started it up and the electric fan came on at start up.

Dose this sound like a bad temp sensor or relay? The A/C was off.

 

[JohnB]

My guess is a relay. If the temp sensor was bad I think your coolent gauge would be pegged also.

Just a side note your engine computer controls the switching of the relay. Which gathers data from the outside temp, engine temp and the speed that you are driving. Very much over engineered for such a simple device.

 

[listerdiesel]

Was the aircon on before you shut the car off?

Our Renault van does that, although in warmer weather rather than the snow we have at present.

It's part of a purge cycle for the aircon as far as I know, but I don't recall seeing anything in RAVE about it for the Disco 2.

Both the fan and the compressor clutch are controlled by the engine ECU, so that the ECU can adjust idle speeds with the compressor is running, but there is also a single wire which seems to have a continuity issue on the schematics. It runs from the fan relay coil to the temp control module, but changes colour on the way!

Both the relays are enabled on the positive side by the same feed, but only the fan has independent control from the ATC ECU, so can be run separately and independently from the compressor.

Peter

 

[brianhoberg]

x3 on the relay. Have you checked it with a multimeter to see what it's drawing?

 

[flyfisher11]

Here was my past question and my own findings in RAVE:

http://www.discoweb.org/forums/showthread.php?t=59767&highlight=DII+electric+fan

 

[DownUnder]

Thanks for the help all. I am going to check it out with this new info.

 

[Two Cold Soakers]

Peter's right.
If the AC is on, the fan will come on; on a D1, anyhow.

 

[adriatic04]

im not sure mine ever kicks on. would that be relay driven as well? I remember it used to and then noticed this past year it seems like it is never on.

reading RAVE on this electric fan, seems simple yet the fan only have a couple very specific settings to run so maybe I am just not hitting those.

 

[flyfisher11]

Peter's right.
If the AC is on, the fan will come on; on a D1, anyhow.

OP is a DII not the same at all.

 

[no694terry]

aren't there two coolant sensors, one controls fan and one to the gauge. and ecu catches a ride on one of them too. correct me if i'm wrong

 

[flyfisher11]

aren't there two coolant sensors, one controls fan and one to the gauge. and ecu catches a ride on one of them too. correct me if i'm wrong

Okay after reading everything you ever wanted to know about DII AND DI air conditioning in RAVE I have discovered my answer. The DI automatically turns on the fans when the AC is selected. On the other hand the DII uses the Ambient temp sensor attached to the front of the condenser fan to tell the ATC ECU to turn the fan on when the temp sensed at the front of the fan is above 82* F and speed is below 80kph. The fan is cut back off when that temp drops below 77*. This has always been a mystery to me due to being fooled by the DI's I wheel with. I also wondered why when the outside air was cool but wheeling with the AC on auto I could get the fan to come on occasionally. This is due to the slow speed on the trail the heat around the condenser fan could swell up from around the radiator, motor, etc enough to fool the ambient temp sensor into thinking the temp is above 82* thus kicking on the fan. Okee dokee now. Condenser fan operation 101.

Enjoy,

Mike


edit: fan will also kick on at coolant temps above 209* regardless of AC settings.