Two Speed Fan Inoperative

pcully · 5th July 2015, 16:09

I know that this question has been asked many times and in many different ways but there would appear to be many answers!

This is the situation on a 2004 CDTi with 101195.on the clock.

I have no fan operation at all and looking through the front I have a gold resistor at approx. two o’clock so we are looking at a two speed fan that has had the resistor upgrade.

With AC off all is well but eventually we do get the temperature gauge to nine o’clock if waiting for car parks or the usual slow city driving but as yet it has not risen beyond this and county driving is no problem but the fan is still not working.

With AC turned on the engine temperature rises quicker and I get erratic running (as someone else said it’s almost like someone is tapping the accelerator pedal) at low revs and even up to 15000 that becomes more pronounced as the temperature rises but again we do not seem to be exceeding the nine o’clock threshold as fare as engine temperature is concerned but engine fan is still not running.

As the fan /temperature control is so linked in with other parameters within the engine could it be that one of these is not releasing the fan command for some reason or another.

What I don’t want to do is get my garage to take the front off the car (probably £200) only to find that the AC needs regassing and that’s it.

Has anyone had these symptoms exactly or is it just so vague regarding the fan etc. that it could be anything?

Peter

Union Wheels · 5th July 2015, 16:27

Hi pcully,
as you have a diesel the first thing to do is to switch on the ignition and press the windscreen demist button on the climate control panel. Then go to the front of the car and look through the grill and see if the fan is turning.

If the fan does not turn suspect an open circuit resistor. If the fan turns, all is well.

The erratic running of the engine may be some other problem such as EGR not closing correctly

Pete.

pcully · 5th July 2015, 16:50

OK I have checked the front end and so fare we have no rotation of the engine fan

Union Wheels · 5th July 2015, 17:05

You have a faulty cooling fan assembly.
The first suspect to try is the gold resistor. If you can place a wire link across resistor and then try the test again, this will tell you if the resistor is open circuit or not. If the fan turns fast the resistor is faulty, if the fan does not turn the you have a faulty motor, a faulty control box (mounted on the rear of the fan assembly) or a missing supply voltage.

chipsceola · 5th July 2015, 21:42

don't be misled by the temp gauge, it stays at 9 o'clock from 75/110C and if and when it does move above that it'll be so quick risk of damage is already high, often and regularly referred to as made of chocolate

pcully · 6th July 2015, 06:23

OK so first job check the fuses ASAP

SD1too · 6th July 2015, 07:22

No Peter; I'm afraid that the first job is to follow Union Wheels' advice in post number 4. Your gold resistor is the prime suspect at the moment.

Simon

Jules · 6th July 2015, 07:46

Very common scenario these days for 2 speed fans !!

The resistor may be u/s.
If it's been u/s for a few months and the AC has been used,
The fan will have only been operating on HIGH speed cycling on and off every few seconds. (this puts excessive current through the high speed relay. They are rated at 40 amps and the 65 amp surge with sudden high speed demand welds the contacts together eventually)

AC should not be used if SLOW speed isn't working as the resistor acts as a "soft start" circuit for the HIGH speed.

If the resistor is OK and high speed relay in the control box is OK you are looking at a duff motor or corrosion in the factory wire joints between the fan plugs/ control box and motor itself or the 80amp fuse.
The fuse very rarely fails but when it does it will be for a reason.

Happy fault finding and if you need a new motor kit look no further

Revotec cooling kit
http://www.the75andztclub.co.uk/foru...d.php?t=189409

Jules whole forum shop index
http://www.the75andztclub.co.uk/foru...splay.php?f=74

Courier services :
£8.95 UK 3-5 working days
£12.95 48 hr service
£15.95 next day (must be ordered before 11am for same day despatch)

This is what the R40 75ZT should have had fitted from day 1
Quality part manufactured by Revotec

Advantages over the OEM motor and other after market equipment:

Waterproof motor
Front mounted motor (away from hot running condenser)
Less current draw for same air movement
Long life motor (designed to run 24hrs for refrigerated cabins etc)
Front stone guard (safety feature plus extra protection for the condenser
Lower cost than OEM but better quality
Easy to fit (installs straight into Siemens/Rover cowling)
12 month Guarantee

Jules · 6th July 2015, 08:01

Quote:

Originally Posted by pcully

I know that this question has been asked many times and in many different ways but there would appear to be many answers!

This is the situation on a 2004 CDTi with 101195.on the clock.

With AC turned on the engine temperature rises quicker and I get erratic running (as someone else said it’s almost like someone is tapping the accelerator pedal) at low revs and even up to 15000 that becomes more pronounced as the temperature rises but again we do not seem to be exceeding the nine o’clock threshold as fare as engine temperature is concerned but engine fan is still not running.

What I don’t want to do is get my garage to take the front off the car (probably £200) only to find that the AC needs regassing and that’s it.

Peter

Peter I forgot to mention the engine hunting is caused by the fact you have no cooling for the engine or AC compressor.

The HP pipe and compressor will be screaming hot without the fan operation and the HP pressure (if connected to R134 gauges will probably be reading 25-30 BAR pressure!!!)

Normal pressure is 6 - 8 BAR so the bottom line is don't use the AC until the fan has been replaced or fixed. You can use the AC above 30 MPH if you really must but are you going to remember to switch it to ECON (economy AC off ) every time speed drops below 30.

kboy · 6th July 2015, 17:43

I have the same problem with my diesel .

I put in a new two sped fan with resistor last year . All was well .

Checked the fan the other day and noted the fan did not come on with demist. Changed the silver resistor to gold and this made no difference.

Put paper clip across the triany and still no life.

How can i test the fan motor or relay pls.

Many thanks

5th July 2015, 16:09	#1
pcully Regular poster Rover 75 Saloon Join Date: Apr 2011 Location: Norwich Posts: 71 Thanks: 2 Thanked 0 Times in 0 Posts	Two Speed Fan Inoperative I know that this question has been asked many times and in many different ways but there would appear to be many answers! This is the situation on a 2004 CDTi with 101195.on the clock. I have no fan operation at all and looking through the front I have a gold resistor at approx. two o’clock so we are looking at a two speed fan that has had the resistor upgrade. With AC off all is well but eventually we do get the temperature gauge to nine o’clock if waiting for car parks or the usual slow city driving but as yet it has not risen beyond this and county driving is no problem but the fan is still not working. With AC turned on the engine temperature rises quicker and I get erratic running (as someone else said it’s almost like someone is tapping the accelerator pedal) at low revs and even up to 15000 that becomes more pronounced as the temperature rises but again we do not seem to be exceeding the nine o’clock threshold as fare as engine temperature is concerned but engine fan is still not running. As the fan /temperature control is so linked in with other parameters within the engine could it be that one of these is not releasing the fan command for some reason or another. What I don’t want to do is get my garage to take the front off the car (probably £200) only to find that the AC needs regassing and that’s it. Has anyone had these symptoms exactly or is it just so vague regarding the fan etc. that it could be anything? Peter Last edited by pcully; 5th July 2015 at 16:11..

5th July 2015, 16:27	#2
Union Wheels Loves to post Honda Accord Tourer i dtec Join Date: Jul 2011 Location: Wakefield Posts: 331 Thanks: 56 Thanked 90 Times in 75 Posts	Hi pcully, as you have a diesel the first thing to do is to switch on the ignition and press the windscreen demist button on the climate control panel. Then go to the front of the car and look through the grill and see if the fan is turning. If the fan does not turn suspect an open circuit resistor. If the fan turns, all is well. The erratic running of the engine may be some other problem such as EGR not closing correctly Pete. __________________ [SIGPIC][/SIGPIC] How to Retrofit Diesel Cruise Control + Loom http://www.the75andztclub.co.uk/foru...87&postcount=1 How to Modify a 3 Speed Fan for CDT & V6 into a 2 Speed with a Resistor. http://www.the75andztclub.co.uk/foru...d.php?t=209920 CDT now gone to new owner, but still on forum Last edited by Union Wheels; 5th July 2015 at 16:29..

5th July 2015, 17:05	#4
Union Wheels Loves to post Honda Accord Tourer i dtec Join Date: Jul 2011 Location: Wakefield Posts: 331 Thanks: 56 Thanked 90 Times in 75 Posts	You have a faulty cooling fan assembly. The first suspect to try is the gold resistor. If you can place a wire link across resistor and then try the test again, this will tell you if the resistor is open circuit or not. If the fan turns fast the resistor is faulty, if the fan does not turn the you have a faulty motor, a faulty control box (mounted on the rear of the fan assembly) or a missing supply voltage. __________________ [SIGPIC][/SIGPIC] How to Retrofit Diesel Cruise Control + Loom http://www.the75andztclub.co.uk/foru...87&postcount=1 How to Modify a 3 Speed Fan for CDT & V6 into a 2 Speed with a Resistor. http://www.the75andztclub.co.uk/foru...d.php?t=209920 CDT now gone to new owner, but still on forum

5th July 2015, 21:42	#5
chipsceola This is my second home Jaguar XF 3.0D Join Date: Nov 2010 Location: Southampton Posts: 4,364 Thanks: 119 Thanked 509 Times in 426 Posts	don't be misled by the temp gauge, it stays at 9 o'clock from 75/110C and if and when it does move above that it'll be so quick risk of damage is already high, often and regularly referred to as made of chocolate __________________ Chips

6th July 2015, 07:22	#7
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: 20,412 Thanks: 1,587 Thanked 3,749 Times in 3,181 Posts	No Peter; I'm afraid that the first job is to follow Union Wheels' advice in post number 4. Your gold resistor is the prime suspect at the moment. Simon __________________ "Whatever is rightly done, however humble, is noble." Sir Henry Royce.

5th July 2015, 16:50	#3
pcully Regular poster Rover 75 Saloon Join Date: Apr 2011 Location: Norwich Posts: 71 Thanks: 2 Thanked 0 Times in 0 Posts	OK I have checked the front end and so fare we have no rotation of the engine fan

6th July 2015, 06:23	#6
pcully Regular poster Rover 75 Saloon Join Date: Apr 2011 Location: Norwich Posts: 71 Thanks: 2 Thanked 0 Times in 0 Posts	OK so first job check the fuses ASAP

6th July 2015, 07:46	#8
Jules This is my second home ZT 260 SE Twilight and 10 other 75 ZT's :O Join Date: Jan 2007 Location: Conwy NORTH WALES Posts: 11,094 Thanks: 512 Thanked 1,116 Times in 763 Posts	Very common scenario these days for 2 speed fans !! The resistor may be u/s. If it's been u/s for a few months and the AC has been used, The fan will have only been operating on HIGH speed cycling on and off every few seconds. (this puts excessive current through the high speed relay. They are rated at 40 amps and the 65 amp surge with sudden high speed demand welds the contacts together eventually) AC should not be used if SLOW speed isn't working as the resistor acts as a "soft start" circuit for the HIGH speed. If the resistor is OK and high speed relay in the control box is OK you are looking at a duff motor or corrosion in the factory wire joints between the fan plugs/ control box and motor itself or the 80amp fuse. The fuse very rarely fails but when it does it will be for a reason. Happy fault finding and if you need a new motor kit look no further Revotec cooling kit http://www.the75andztclub.co.uk/foru...d.php?t=189409 Jules whole forum shop index http://www.the75andztclub.co.uk/foru...splay.php?f=74 Courier services : £8.95 UK 3-5 working days £12.95 48 hr service £15.95 next day (must be ordered before 11am for same day despatch) This is what the R40 75ZT should have had fitted from day 1 Quality part manufactured by Revotec Advantages over the OEM motor and other after market equipment: Waterproof motor Front mounted motor (away from hot running condenser) Less current draw for same air movement Long life motor (designed to run 24hrs for refrigerated cabins etc) Front stone guard (safety feature plus extra protection for the condenser Lower cost than OEM but better quality Easy to fit (installs straight into Siemens/Rover cowling) 12 month Guarantee __________________ [SIGPIC][/SIGPIC] Newbies do now!! 1. Plenum drains..all 3 or 4 year dependent 2. Cooling fan..All speeds functioning 3. Bonnet cable divider block

6th July 2015, 17:43	#10
kboy Regular poster rover 75 cdti se Join Date: Feb 2014 Location: london Posts: 35 Thanks: 4 Thanked 0 Times in 0 Posts	Same here I have the same problem with my diesel . I put in a new two sped fan with resistor last year . All was well . Checked the fan the other day and noted the fan did not come on with demist. Changed the silver resistor to gold and this made no difference. Put paper clip across the triany and still no life. How can i test the fan motor or relay pls. Many thanks