Condenser fans

Hello all

I might be going over old ground, but i just need clarification on correct operation. As far as i'm aware, when pressure builds up, BOTH fans will cut in at SLOW speed. Then if the pressure builds up even more, BOTH fans will switch to HIGH speed and then drop down to SLOW speed when the pressure drops?

At the moment, as soon as the ignition is switched on, the right hand fan (looking from the front) comes on at slow speed. I have found out that this is caused by someone bridging the wires by the single pressure switch. I am assuming it is a faulty switch and as everything on these Range Rovers, the previous owners couldn't be arsed to fix it. I have put power to the left fan, that works, but only on at high speed. I have disconnected the bridged wires to the right hand fan and it doesn't come on with the ignition. I have run the air con at "LO" for about 10 minutes and the fan/s do not kick in and temperature stays cold in the car (i know it's not the hottest of days!!). I have checked the condenser temperature, but that isn't really even warm. I am assuming that is down to the viscous fan doing most of the cooling?

all the previous posts i have read, indicate that the condenser fans hardly need to come on at all, is this right?

Why does the left fan only come on at high speed? There are no blown fuses and the relays seem fine.

Thanks
Kev

Could all this be down to a faulty pressure switch?

It should not be possible for one fan to come on at half speed as they are connected in series to run at half speed. Could be the non running fan has partially siezed bearing so it has not enough power on half speed to turn. This could cook the motor.

The fans never come on as far as I can detect on my 2000 DHSE even in 30C temperatures, although when tested they work fine. In my case I'm pretty sure it's low gas pressure in the aircon failing to operate the switches.

after further investigation, it is actually the tri-pressure switch (that goes into the top of the drier), that the wires have been bridged to make the right hand fan run at half speed. I'm at a loss, any ideas?

Thanks Kev

The fans hardly ever come on even with the system fully gassed and fault free. It's because the condenser is about the same size as the radiator and sits directly in front of it so the viscous fan does the cooling work, problem can be though that it pushes pre warmed air over the radiator in hot weather. To protect against damage due to engine overheating, especially when stationary, the electric fans will cut in if the coolant temperature gets dangerously high (Mine does on the odd occaision we get very hot weather). With a lot of "Normal" cars, the condenser is mounted away from the engine radiator and rely solely on the condenser fan(s) for cooling..as is the case on Er Indoors Vectra and the fans work their butts off cooling the gas on that.
It's just a P38 thing.:behindsofa:

Just to add...probably someone is under the impression that they should run most of the time or have had overheating problems in the past and "Jumpered" the switch to improve the cooling. Datatek has already outlined how they work.
Condenser fan function can easily be checked with either Test Book/Rovacom/Autologic diagnostics by accessing the engine ecu with the software,

Thanks Irish (yet again!). It's just i saw those wires scotch-locked together and i ask myself "why". Everything seems to work ok (aircon wise), but do i leave the wires as they are, or just remove the scotchlock. Maybe i should get my OCD checked out again!

Kev

Just remove it, you will probably find that it will make no difference except the fans won't run.
If you do get grief...put it back until you get things checked out.

Well today i removed the scotchlock bridging the wires together, on the dual pressure switch, that made the left hand fan run all the time, when the ignition was on. I then took the multi-plug off the single pressure switch and bridged that with the ignition on......nothing! As i see it, that should bring both condenser fans on at half speed? I am now assuming that is why the wires were bridged.

Kev