cooling fan

[bigdaddystew]

Hi guys..I need some help..cooling fan was not coming on.. replaced the resistor to my fan to the new gold one..fan would still not come on..saw a thread which indicated if the aircon is low on pressure this would happen..just had the aircon recharged and its blowing very cold air which it wasnt doing before and the fan is now coming on but cuts out for about 5 seconds and then switches on for around 10 seconds and repeats this cycle..can anyone help on where I go from here..any help appreciated.... regards stewart.

[stevestrat]

Sounds as if the fan is cycling at high speed indicating there is still a problem with the low speed. Take it you have done the demister test, start the engine, aircon off, press the demist button, go to the front of the car and after a few seconds you should hear the fan running at low speed. Where did you get the resistor, it is a Jules one or Ebay?

[Rick-sta]

As Steve said above, the highspeed kicking in on and off every few seconds points towards a failed resistor. May be worth double checking the resistor's wiring or maybe you've been unlucky and received a faulty one.

[RodgerD]

Originally Posted by Rick-sta

As Steve said above, the highspeed kicking in on and off every few seconds points towards a failed resistor. May be worth double checking the resistor's wiring or maybe you've been unlucky and received a faulty one.

Or low speed relay stuck open. Bond across the resister ends will confirm if the resister is kaput as fan should run at high speed, if it doesn't check low speed relay mechanically and electrically. High and low speed relays are feed from the engine compartment fuse box, with the relay solenoid earth return being made via the ECM (engine ECU).

Getting to the fan relays is a right pain, bumper off, slam panel and crash bar and then remove the fan and cowling. Relays live in a box at the top RH corner of the fan assy.

[bigdaddystew]

Hi guys..thanks for your replies..just an update..tried the demist button with engine running...fan came on after a few seconds..went off after around 20 seconds..came on again after around 5 seconds and continued like that..does this indicate a certain problem...resistor came from ebay..link as follows..http://www.ebay.co.uk/itm/Rover-75-M.../131505668654?
regards stewart

[RodgerD]

Originally Posted by bigdaddystew

Hi guys..thanks for your replies..just an update..tried the demist button with engine running...fan came on after a few seconds..went off after around 20 seconds..came on again after around 5 seconds and continued like that..does this indicate a certain problem...resistor came from ebay..link as follows..http://www.ebay.co.uk/itm/Rover-75-M.../131505668654?
regards stewart

It should stay on all the time. Bridge across the resister whilst the fan isn't running and do the check again. You need a bit of heavy gauge wire and a couple small cable ties to hold the bare ends in contact with the ends of the resistor. If it stays on all the time, your problem lies within the resistor. If no change you need to look at the cooling fan relays and wiring to them next.

[bigdaddystew]

Thanks Roger..I will have to get a couple more of the solder sleeves as I will have to go into them to bridge the wiring..Is the cooling fan relay the one behind the cooling fan and shroud and can these be purchased..thanks stewart

[RodgerD]

Originally Posted by bigdaddystew

Thanks Roger..I will have to get a couple more of the solder sleeves as I will have to go into them to bridge the wiring..Is the cooling fan relay the one behind the cooling fan and shroud and can these be purchased..thanks stewart

The relays ( 2 off) live in a control box in the top RH side (as you look toward the engine) of the fan cowling. Low speed relay is the smaller of the two. They are standard automotive relays, information will be on relay.