Rover 75 Con SE 2.0 CDTi - Radiator Cooling Fan Always On

cashford · 21st March 2024, 14:39

Hi All

I know there have been many posts on this in the past but most seem a long time ago so I thought I'd ask what might be the same question again as the 'fix' options might be different now.

In the last few days the radiator fan has starting coming on just a second or two after switching on the ignition (engine does not need to be on) and remaining on the whole time the car is running before finally stopping about 5-10 seconds after the ignition is turned off.

Based on all the posts I have found I have done ... listed below, I think it's probable something to do with PCB or relays mounted in the side of the radiator fan housing.

I have not had the front off the car yet, but from peering through the grille it seems my radiator does NOT have a resistor on it.

The tests/checks I have done are:

1. Air con off and in Econ mode.. Fan stays on. Air con/Fan switched completely to off... Fan stays on. Front Demist switched on... Fan remains.... Basically no impact whatever I change there.

2. Fan seems to just come on irrespective of whether the engine is running or not but does stop shortly after the ignition is switched off.. From what I've read this seems to rule out a relay in the PCB module being stuck

3. Checked connections behind OSF headlight so signs of water ingress.

4. Checked the dashboard display diagnostics to check temperature is being read correctly by the sensor... starts off about 10 degrees (probably right of the weather now) and rises as the car is driven to about 90 ish

5. Temperature gauge on the dash also works as you would expect and ends up at the 9 O'Clock Position so probably not the Temperature sensor on the engine

6. Disconnected the Aircon Trinary switch to see if the fan stopped or sped up... no impact... just kept running

So based on the fact that there appears to be no resistor I think it must be the radiator fan PCB, or possibly (I think I have read) the PWM signal wire?

I guess my questions are simply this... I am no genius .. indeed all I have done to get this far is follow other posts on the forum so...

Do you guys who are far cleverer than me agree with my thoughts?
Do you have any other suggestions
Most importantly, if you do agree with me... Does anyone know how I can get the PCB repaired.... I see there have previously been some members that can help here but the posts were very old, so hence the reason for asking the questions afresh.

Thank you all so much.

CHARLES

SD1too · 21st March 2024, 22:06

Quote:

Originally Posted by cashford

Most importantly, if you do agree with me... Does anyone know how I can get the PCB repaired....

Hello Charles,

Club member FrenchMike is your man for the diesel PCB. Years ago he explained to me how it worked at component level and has occasionally repaired them for club members. After a quiet period I think I saw a post from him only a few days ago so try a message or an e-mail.

Simon

cashford · 22nd March 2024, 07:33

Hi Simon

Thanks for this.. I'll PM him right now. Appreciate the info

Charles

cashford · 25th March 2024, 09:11

Quick question - It's going take me a few weeks to have time to get this fixed... Can I drive the car normally while the fan is just running all the time... I'm guessing it will be fine but just wanted to check with people wiser than me!

Also, if I can't get a replacement PCB or a repair, is there a way I can replace the whole fan assembly with a different type, IE the type with the resistor or will this require other changes too?

Thanks Again

CHARLES

Arctic · 25th March 2024, 09:37

Quote:

Originally Posted by cashford

Quick question - It's going take me a few weeks to have time to get this fixed... Can I drive the car normally while the fan is just running all the time... I'm guessing it will be fine but just wanted to check with people wiser than me!

Also, if I can't get a replacement PCB or a repair, is there a way I can replace the whole fan assembly with a different type, IE the type with the resistor or will this require other changes too?

Thanks Again

CHARLES

Hi Charles.
You can change the fan over with one the same, r one with the gold resistor it will be plug and play, if you were closer to us in the West midlands we could have checked this out for you this weekend at our meet, Saturday.

I carry spare refurbished fans with me at the meet, i also have a couple of unobtainable PCB boards, i have not heard from French mike for ages i have five PCB that need sorting out, but have also contacted another chap local to us whom may be able to help with sorting out the PCB, waiting on his reply.

Driving the car with the fan on all the time will only wear out the brushes quicker, it should not do any other harm, same goes if you remove the fuse to the fan and it does not run at all, i doubt you will over heat a diesel unless maybe it was very hot summer and you were towing a caravan.

Either way you will need to get to the black relay box with the relay's and PCB in.

1

https://www.midlandsnanomeets.co.uk/meets_2014.html

cashford · 25th March 2024, 11:24

Hi Acrtic - Thanks for the reply... I didn't know about the NanoMeets... They sound brilliant! I'll deffo come up for one, sounds like a good day out and a good excuse to take my old girl (The 75 that is, not the wife LOL!) on a decent drive.

Re the PCB, are you saying you have a working spare? If so could you PM me to see if we can sort something out? - You could be my saviour!!! Just need to get to mine first LOL!

Do you think reading through the tests I have done and the results that it is most likely the PCB at fault?

Thanks again - Charles

WillyHeckaslike · 25th March 2024, 11:38

FenchMike's profile shows that he has not logged in since 26th July 2022 and I think that at least one member has since tried to contact him to no avail. He was a regular poster so his absence of 20 months to date could suggest that he is either taking a break from the site or that he is no longer available for whatever reason.

21st March 2024, 14:39	#1
cashford Newbie Rover 75 Saloon Join Date: Nov 2023 Location: Bournemouth Posts: 19 Thanks: 0 Thanked 0 Times in 0 Posts	Rover 75 Con SE 2.0 CDTi - Radiator Cooling Fan Always On Hi All I know there have been many posts on this in the past but most seem a long time ago so I thought I'd ask what might be the same question again as the 'fix' options might be different now. In the last few days the radiator fan has starting coming on just a second or two after switching on the ignition (engine does not need to be on) and remaining on the whole time the car is running before finally stopping about 5-10 seconds after the ignition is turned off. Based on all the posts I have found I have done ... listed below, I think it's probable something to do with PCB or relays mounted in the side of the radiator fan housing. I have not had the front off the car yet, but from peering through the grille it seems my radiator does NOT have a resistor on it. The tests/checks I have done are: 1. Air con off and in Econ mode.. Fan stays on. Air con/Fan switched completely to off... Fan stays on. Front Demist switched on... Fan remains.... Basically no impact whatever I change there. 2. Fan seems to just come on irrespective of whether the engine is running or not but does stop shortly after the ignition is switched off.. From what I've read this seems to rule out a relay in the PCB module being stuck 3. Checked connections behind OSF headlight so signs of water ingress. 4. Checked the dashboard display diagnostics to check temperature is being read correctly by the sensor... starts off about 10 degrees (probably right of the weather now) and rises as the car is driven to about 90 ish 5. Temperature gauge on the dash also works as you would expect and ends up at the 9 O'Clock Position so probably not the Temperature sensor on the engine 6. Disconnected the Aircon Trinary switch to see if the fan stopped or sped up... no impact... just kept running So based on the fact that there appears to be no resistor I think it must be the radiator fan PCB, or possibly (I think I have read) the PWM signal wire? I guess my questions are simply this... I am no genius .. indeed all I have done to get this far is follow other posts on the forum so... Do you guys who are far cleverer than me agree with my thoughts? Do you have any other suggestions Most importantly, if you do agree with me... Does anyone know how I can get the PCB repaired.... I see there have previously been some members that can help here but the posts were very old, so hence the reason for asking the questions afresh. Thank you all so much. CHARLES

22nd March 2024, 07:33	#3
cashford Newbie Rover 75 Saloon Join Date: Nov 2023 Location: Bournemouth Posts: 19 Thanks: 0 Thanked 0 Times in 0 Posts	Hi Simon Thanks for this.. I'll PM him right now. Appreciate the info Charles

25th March 2024, 09:11	#4
cashford Newbie Rover 75 Saloon Join Date: Nov 2023 Location: Bournemouth Posts: 19 Thanks: 0 Thanked 0 Times in 0 Posts	Quick question - It's going take me a few weeks to have time to get this fixed... Can I drive the car normally while the fan is just running all the time... I'm guessing it will be fine but just wanted to check with people wiser than me! Also, if I can't get a replacement PCB or a repair, is there a way I can replace the whole fan assembly with a different type, IE the type with the resistor or will this require other changes too? Thanks Again CHARLES

25th March 2024, 11:24	#6
cashford Newbie Rover 75 Saloon Join Date: Nov 2023 Location: Bournemouth Posts: 19 Thanks: 0 Thanked 0 Times in 0 Posts	Hi Acrtic - Thanks for the reply... I didn't know about the NanoMeets... They sound brilliant! I'll deffo come up for one, sounds like a good day out and a good excuse to take my old girl (The 75 that is, not the wife LOL!) on a decent drive. Re the PCB, are you saying you have a working spare? If so could you PM me to see if we can sort something out? - You could be my saviour!!! Just need to get to mine first LOL! Do you think reading through the tests I have done and the results that it is most likely the PCB at fault? Thanks again - Charles

25th March 2024, 11:38	#7
WillyHeckaslike This is my second home Rovers 75 & 25 Join Date: Oct 2010 Location: Wearside Posts: 4,527 Thanks: 543 Thanked 709 Times in 511 Posts	FenchMike's profile shows that he has not logged in since 26th July 2022 and I think that at least one member has since tried to contact him to no avail. He was a regular poster so his absence of 20 months to date could suggest that he is either taking a break from the site or that he is no longer available for whatever reason.