Air con fans...

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jerrytlr

New Member
Posts
307
Location
Dordogne, France
Just had the aircon regassed and, much to my surprise, it now works (for the first time since I got the car almost a year ago)!

Big question of course is how long will it stay working for.....

One question though - I have noticed the aircon fans aren't running even though the aircon is nice and cool - are they supposed to run all the time, or just when needed?

Cheers,

Jerry
 
They will only come on if the aircom is working flat out on a hot day. The normal cooling fan and air moving through the condensor will cool the system sufficiently if it's not a very warm day. Even then only one fan may come on, it is only when the refridgerant is very hot that both will work.
 
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That would certainly explain it .....

Now, I know you are very clued up about these fans as you have designed the mod to use them to cool the engine ilo the viscous fan :) - is there a quick and easy way to test them, perhaps by jumpering a relay contact somewhere?

Cheers

Jerry
 
Relay 13 fan 1 relay 14 fan 2. Looking over the wing the two green relays at top left of fuse box. Below the line of yellow ones.
 
The facility to force the condenser fan operation is available in the engine ecu module (GEMS or Motronic (Thor)) on faultmate, not the Becm.
Stupidly, Land Rover decided to fit the condenser in front of the engine radiator on the P38 (Petrol & diesel) which means that all of the cool air passes through the condenser first. This ar is pulled through by the more than adequate engine viscous fan and as a result, the condenser is adequately cooled by the engine fan and the condenser fans are hardly ever energised via the trinary switch unless the ambient air temp. is high.
The downside of the design is that if the condenser is taking the lions share of the airflow, the air that has passed through the condenser has been warmed prior to reaching the engine radiator...as a result, the engine radiator plays second fiddle as far as cool air flow is concerned.
When I owned my P38 (V8), I never had the fans cut in, yet the fans worked perfectly when forced on with Faultmate. If the aircon is working well, don't worry about it.
The most important thing is that the engine cooling is working.
 
Irishrover said:
The facility to force the condenser fan operation is available in the engine ecu module (GEMS or Motronic (Thor)) on faultmate, not the Becm.
Stupidly, Land Rover decided to fit the condenser in front of the engine radiator on the P38 (Petrol & diesel) which means that all of the cool air passes through the condenser first. This ar is pulled through by the more than adequate engine viscous fan and as a result, the condenser is adequately cooled by the engine fan and the condenser fans are hardly ever energised via the trinary switch unless the ambient air temp. is high.
The downside of the design is that if the condenser is taking the lions share of the airflow, the air that has passed through the condenser has been warmed prior to reaching the engine radiator...as a result, the engine radiator plays second fiddle as far as cool air flow is concerned.
When I owned my P38 (V8), I never had the fans cut in, yet the fans worked perfectly when forced on with Faultmate. If the aircon is working well, don't worry about it.
The most important thing is that the engine cooling is working.
Click to expand...

Unlike the Gems or Thor, the diesel ECU has no control over the fans.:)
 
jerrytlr said:
That would certainly explain it .....

Now, I know you are very clued up about these fans as you have designed the mod to use them to cool the engine ilo the viscous fan :) - is there a quick and easy way to test them, perhaps by jumpering a relay contact somewhere?

Cheers

Jerry
Click to expand...

Pull the blue/black wire off the dual pressure switch and ground it, that will give you a full function test of the relays and fans, it will also ensure that there is no break in the loom as there was on mine preventing the fans from ever working:)


For ease of access remove the small (fog light location for some models) grill under the bumper in front of the auto gearbox oil cooler. Locate the Blue/black wire on the receiver/dryer dual pressure switch.
 
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