Air conditioning fan relay switch - Page 2

SD1too · 7th July 2012, 23:20

Quote:

Originally Posted by Charles

Have now tried this: the fan doesn't seem to move at all.

Thanks Charles. This tells us that you have lost your slow fan speed, which is a very common fault. Now I have one more easy check for you to perform.

Looking in through the radiator grille again, can you see a silver rectangular resistor with a wire at each end mounted on the fan surround at about the one o'clock position? Your car may or may not have one, depending upon the type of fan system fitted. Please report back.

Simon.

Charles · 8th July 2012, 08:34

I can't see one. I understand this means that I have the original 3-speed fan as opposed to the more recent 2-speed type.

SD1too · 8th July 2012, 08:43

Yes that's right. What's happened is that one of the motor brushes has worn away to nothing resulting in the loss of your slow and medium fan speeds. It happens to all the three speed motors eventually. Both these speeds are used by the air conditioning, so if they're not functioning the system becomes stressed and results in the whining noise you've heard. The same speeds are, of course, needed to keep the engine cool as well, so you need to get this repaired a.s.a.p. Here are the options:

New brushes can be fitted, but that only makes financial sense if you can do it yourself. The alternative is to replace the three speed motor and control box assembly with either a MG Rover 2 speed system (which is fully compatible but rather expensive) or an aftermarket Kenlowe fan system available from club member and trader Jules. You might like to contact him for full details and prices.

Simon.

Charles · 8th July 2012, 11:13

Thanks for this, Simon. At least I now know what the problem is, and what the options are. I'll give it some thought, and hopefully also see Dave next weekend.

Charl;es.

lovema75 · 8th July 2012, 12:07

Opening up the motor and replacing the brushes isn't actually too bad a job, I am a complete novice but managed it with the endless patience of forum members here, and it cost me £10!!!!

(do you get the feeling I am chuffed?)

Charles · 8th July 2012, 12:26

That's encouraging. I'm something of a novice myself but learning rapidly, largely thanks to the incredibly helpful members of this forum. Just not sufficiently confident to start taking the front end off on my own!

8th July 2012, 08:43	#13
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: 20,344 Thanks: 1,587 Thanked 3,749 Times in 3,181 Posts	Yes that's right. What's happened is that one of the motor brushes has worn away to nothing resulting in the loss of your slow and medium fan speeds. It happens to all the three speed motors eventually. Both these speeds are used by the air conditioning, so if they're not functioning the system becomes stressed and results in the whining noise you've heard. The same speeds are, of course, needed to keep the engine cool as well, so you need to get this repaired a.s.a.p. Here are the options: New brushes can be fitted, but that only makes financial sense if you can do it yourself. The alternative is to replace the three speed motor and control box assembly with either a MG Rover 2 speed system (which is fully compatible but rather expensive) or an aftermarket Kenlowe fan system available from club member and trader Jules. You might like to contact him for full details and prices. Simon. __________________ "Whatever is rightly done, however humble, is noble." Sir Henry Royce.

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8th July 2012, 08:34	#12
Charles Avid contributor Rover 75 2.0 V6 Connossieur SE Join Date: Jul 2008 Location: York Posts: 183 Thanks: 13 Thanked 12 Times in 6 Posts	I can't see one. I understand this means that I have the original 3-speed fan as opposed to the more recent 2-speed type.

8th July 2012, 11:13	#14
Charles Avid contributor Rover 75 2.0 V6 Connossieur SE Join Date: Jul 2008 Location: York Posts: 183 Thanks: 13 Thanked 12 Times in 6 Posts	Thanks for this, Simon. At least I now know what the problem is, and what the options are. I'll give it some thought, and hopefully also see Dave next weekend. Charl;es.

8th July 2012, 12:07	#15
lovema75 This is my second home 75 Tourer CDT Join Date: Dec 2011 Location: Enfield Posts: 3,925 Thanks: 63 Thanked 431 Times in 237 Posts	Opening up the motor and replacing the brushes isn't actually too bad a job, I am a complete novice but managed it with the endless patience of forum members here, and it cost me £10!!!! (do you get the feeling I am chuffed?)

8th July 2012, 12:26	#16
Charles Avid contributor Rover 75 2.0 V6 Connossieur SE Join Date: Jul 2008 Location: York Posts: 183 Thanks: 13 Thanked 12 Times in 6 Posts	That's encouraging. I'm something of a novice myself but learning rapidly, largely thanks to the incredibly helpful members of this forum. Just not sufficiently confident to start taking the front end off on my own!