V6 2 speed fan not working

thanos.m · 13th March 2022, 13:49

Hi all,

A couple of days ago I took out my 75 out to pick up some friends I hadn't driven the car for a month or so as I now have another daily and I noticed I have no cooling fan at all. It's a 2 speed with a gold resistor the car had a new rad and fan fitted according to the service history in 2016. So far I've done the following tests demist button fan does not respond I've tried the paper clip on the trinary switch again no fan. Setting the AC to low the AC compressor does kick in but again no fan.

I had to take off the bumper to fix the bonet cable checked the wiring all seemed fine and intact. Also I connected up my laptop with Toaf tried to actuate the fan from there and again nothing happens I dont hear any relay clicks or anything of that sort either. Interestingly before when the fan was working fine I always used to get a code for medium fan speed thinking that this was probably because the car was converted to a 2 speed from a 3 now I'm not getting that code either.

From what I'm reading I should also check the fusable link but its also unlikely to be the corporate. The car was waiting for more work to be done at specialist but his about 150 miles away so I'd have to drive with no fan is there anything else I should check? and is there a way to hardwire the fan in to get me there?

stevestrat · 13th March 2022, 14:04

There are gold resistors and gold resistors, quality varies a lot, that would be my first port of call. TOAF was set up for the three speed system so will always look for the middle speed and regard not finding it as a fault.

thanos.m · 13th March 2022, 15:35

Thanks for the reply unfortunately as I dont have a drive I wont be able to solder one in is there any way I to test or bypass it to have the constantly on ?

vitesse · 13th March 2022, 15:47

Strange that neither speed is working, usually when I've tested 2 speed fans with a dead resistor the other speed works fine. Wonder if the relays aren't being energised by the ECU or if there's a power problem - not that easy to access the control box unfortunately.

Regards

bsafly · 13th March 2022, 16:07

As both fan speeds are inoperative it might be worth a look at the fan circuit fuse(s).
Only a thought, but an easy thing to check.

SD1too · 13th March 2022, 16:22

Just checking Thanos that when you carried out your tests the engine was running.

Simon

COLVERT · 13th March 2022, 22:39

Fan brushes, maybe ??

thanos.m · 14th March 2022, 12:02

The issue seems to get even more complicated I tested continuity and I do have continuity I once again started the engine demist on AC compressor kicked in as per usual and then the fun spun and down about 3 times and then it stayed in low speed for a about half a minute and the turned off again. I tried again the test with the paper clip on the the trinary switch nothing. I then plugged the trinary switch again started the engine tried demist and low setting on the AC and the compressor would no longer kick in nor did the fan. I plugged toaf back in and I tried to actuate the fan I could hear both relays low and high speed relays kick on as well the AC compressor I also did another continuity test and all checked out but I'm not getting a fan nor the AC compressor

SD1too · 15th March 2022, 07:06

Is your refrigerant charge low?

Simon

Arctic · 15th March 2022, 09:20

Quote:

Originally Posted by COLVERT

Fan brushes, maybe ??

HI Jon.
I have seen that first picture before

it's a four wire three speed fan, from a diesel.

1

Whereas the Op as a two wire 2 speed fan with gold resistor on a 2.5 petrol

13th March 2022, 13:49	#1
thanos.m Avid contributor Rover 75 saloon Join Date: May 2019 Location: West Sussex Posts: 220 Thanks: 54 Thanked 41 Times in 26 Posts	V6 2 speed fan not working Hi all, A couple of days ago I took out my 75 out to pick up some friends I hadn't driven the car for a month or so as I now have another daily and I noticed I have no cooling fan at all. It's a 2 speed with a gold resistor the car had a new rad and fan fitted according to the service history in 2016. So far I've done the following tests demist button fan does not respond I've tried the paper clip on the trinary switch again no fan. Setting the AC to low the AC compressor does kick in but again no fan. I had to take off the bumper to fix the bonet cable checked the wiring all seemed fine and intact. Also I connected up my laptop with Toaf tried to actuate the fan from there and again nothing happens I dont hear any relay clicks or anything of that sort either. Interestingly before when the fan was working fine I always used to get a code for medium fan speed thinking that this was probably because the car was converted to a 2 speed from a 3 now I'm not getting that code either. From what I'm reading I should also check the fusable link but its also unlikely to be the corporate. The car was waiting for more work to be done at specialist but his about 150 miles away so I'd have to drive with no fan is there anything else I should check? and is there a way to hardwire the fan in to get me there?

13th March 2022, 14:04	#2
stevestrat This is my second home ZT260 #243 (resting) Join Date: May 2010 Location: Prestonpans Posts: 22,455 Thanks: 650 Thanked 4,624 Times in 3,358 Posts	There are gold resistors and gold resistors, quality varies a lot, that would be my first port of call. TOAF was set up for the three speed system so will always look for the middle speed and regard not finding it as a fault. __________________ Steve T4 Location Map

13th March 2022, 16:07	#5
bsafly Just going about! Rover 75 CDTi Connie SE Tourer starlight silver and serpents. MG ZT-T 190+ in Raven Black. Join Date: Mar 2016 Location: Great Leighs Posts: 468 Thanks: 626 Thanked 167 Times in 110 Posts	As both fan speeds are inoperative it might be worth a look at the fan circuit fuse(s). Only a thought, but an easy thing to check. __________________

13th March 2022, 16:22	#6
SD1too Doesn't do things by halves Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model. Join Date: Mar 2007 Location: Former Middlesex Posts: 20,338 Thanks: 1,587 Thanked 3,749 Times in 3,181 Posts	Just checking Thanos that when you carried out your tests the engine was running. Simon __________________ "Whatever is rightly done, however humble, is noble." Sir Henry Royce.

15th March 2022, 07:06	#9
SD1too Doesn't do things by halves Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model. Join Date: Mar 2007 Location: Former Middlesex Posts: 20,338 Thanks: 1,587 Thanked 3,749 Times in 3,181 Posts	Is your refrigerant charge low? Simon __________________ "Whatever is rightly done, however humble, is noble." Sir Henry Royce.

13th March 2022, 15:35	#3
thanos.m Avid contributor Rover 75 saloon Join Date: May 2019 Location: West Sussex Posts: 220 Thanks: 54 Thanked 41 Times in 26 Posts	Thanks for the reply unfortunately as I dont have a drive I wont be able to solder one in is there any way I to test or bypass it to have the constantly on ?

13th March 2022, 15:47	#4
vitesse I really should get out more....... Rover 75 Saloon Join Date: Jul 2011 Location: Gävle Posts: 2,528 Thanks: 395 Thanked 823 Times in 652 Posts	Strange that neither speed is working, usually when I've tested 2 speed fans with a dead resistor the other speed works fine. Wonder if the relays aren't being energised by the ECU or if there's a power problem - not that easy to access the control box unfortunately. Regards

14th March 2022, 12:02	#8
thanos.m Avid contributor Rover 75 saloon Join Date: May 2019 Location: West Sussex Posts: 220 Thanks: 54 Thanked 41 Times in 26 Posts	The issue seems to get even more complicated I tested continuity and I do have continuity I once again started the engine demist on AC compressor kicked in as per usual and then the fun spun and down about 3 times and then it stayed in low speed for a about half a minute and the turned off again. I tried again the test with the paper clip on the the trinary switch nothing. I then plugged the trinary switch again started the engine tried demist and low setting on the AC and the compressor would no longer kick in nor did the fan. I plugged toaf back in and I tried to actuate the fan I could hear both relays low and high speed relays kick on as well the AC compressor I also did another continuity test and all checked out but I'm not getting a fan nor the AC compressor

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