condencer fans

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Not quite true, see below...

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Basically it has to be a really hot day for them to come on. Ive only ever seen/heard mine on twice, once was when it was a really hot day and they were busy doing their job and the second time was when I was trying to find a fault within the A/C system which was causing the book symbol to show and I activated them manually.

-Wills :)
 
To activate them manually you unplug the connector to the single pressure switch and can use a paper-clip to short the 2 pins on the connector (shown as 2 in the FIRST diagram).

Be careful when doing this as this will log a fault in the HeVAC ECU and while it won't cause the book to stay or anything permanently if you can't find the fault and then take it to a mechanic and he see's that fault logged he might blame the switch/fans and charge you for work that isn't needed.

If I remember correctly as well they come on when the engine is getting very hot, i.e. the temp is rising and would cause an engine overheat AND if there is a wide open throttle situation, i.e. you are giving it the lead foot treatment. However I THINK this only applies to the V8 models.

Be careful if you start messing about with paper-clips though - why do you want to see if they work?? Have you got a problem with the system??

-Wills :)
 
In the Classic they come on when coolant temp is 95deg C. I bypassed the (faulty)switch in my 3.9RRC and used it in effect as a Kenlowe fan when I had no engine mounted fan. Went fine all last summer. I replaced the thermo switch for the winter and its still going fine since. In fact I still have no VC fan as some time in the past someone fitted a pre serpentine (which runs in the opposite direction) fan blade to mine so it was blowing instead of sucking air through the radiator giving overheating problems at urban speeds, fine when stopped or travelling quickly but would overheat at 15 to 25mph. Took me a while to cop the problem!
 
hi guys,thanks for the replies.the reason iam asking about the fans, is because i read that too ,could be reason car is overheating,iam just trying to cover all the bases for this overheating problem. thanks
 
wills said:
To activate them manually you unplug the connector to the single pressure switch and can use a paper-clip to short the 2 pins on the connector (shown as 2 in the FIRST diagram).

Be careful when doing this as this will log a fault in the HeVAC ECU and while it won't cause the book to stay or anything permanently if you can't find the fault and then take it to a mechanic and he see's that fault logged he might blame the switch/fans and charge you for work that isn't needed.

If I remember correctly as well they come on when the engine is getting very hot, i.e. the temp is rising and would cause an engine overheat AND if there is a wide open throttle situation, i.e. you are giving it the lead foot treatment. However I THINK this only applies to the V8 models.

Be careful if you start messing about with paper-clips though - why do you want to see if they work?? Have you got a problem with the system??

-Wills :)
Click to expand...

mine got hot once, the red light in temp gauge came on and i switched off instantly as i was stationary and only idling anyway, the fault was a defective fan switch i fitted, cost me a fortune as well, crap from scorpion racing!
the two front fans never came on, well if they did they didnt come on quick enough to help.......

how is the fault code created?

is it the removal of the plug from the switch? if so could you tap into the 2 wires and run to a switch for additional cooling at times of need, instigating the fans before the engine gets too hot to start with, and as the plug wont be removed maybe it wont log a fault! :)
 
redrange said:
mine got hot once, the red light in temp gauge came on and i switched off instantly as i was stationary and only idling anyway, the fault was a defective fan switch i fitted, cost me a fortune as well, crap from scorpion racing!
the two front fans never came on, well if they did they didnt come on quick enough to help.......

how is the fault code created?

is it the removal of the plug from the switch? if so could you tap into the 2 wires and run to a switch for additional cooling at times of need, instigating the fans before the engine gets too hot to start with, and as the plug wont be removed maybe it wont log a fault! :)
Click to expand...

hmmm, well in RAVE you have this which is taken from the ETM...

For the petrol option, when the signal enters the ECM, the ECM will switch the output on/off to the fusebox. The ECM will switch the output on sometimes for engine cooling reasons even though the engine has been turned off.
Click to expand...

So, im not totally sure either way. Ive read somewhere else, although I can't find the PDF that had it in now, that they should kick in when extra cooling is needed.

The fault that is created is something like a 'short to ground' fault or similar, its some sort of short circuit fault. I can't remember now as it was ages ago when I tested the fans. It illuminates the book symbol straight away though.

It's an interesting idea on the manual switch option but remember the A/C has to be ON before the fans can be operated anyway (read the diagram above to see what I mean). You also have to remember that the fans will only run at a slow speed by default unless the pressure in the A/C system is above a certain level.

Have a look through the ETM if you want to see how the whole system works :)

-Wills :)
 
i spose an easier and less complicated option is to put an additional feed/earth to the fans when required!
i will check mine though as i have never seen them going in the 3 years i owned it!
 
I had the same thing in my Classic, I over heated, got out to check the fans to see them sitting happily doing nothing. Turned out the coolant temp switch was faulty. I know the P38 is completely different with the BECM and all that and wills knows his way around it better than most but in the classic the coolant switch was on a different circuit to the aircon switch so it would come on irrespective of the position of the aircon switch. The RRC coolant temp switch was a simple 2 wire switch (not an earth switch) which I bypassed with a simple jumper wire to turn the fans on permanently (while ignition on) until I got a new switch. I don't know how different the 4.6 is to the 3.9 in that regard but it might be worth a look as it should not fault out the BeCM if its the same although I'm open to correction by wills on that:)
 
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