MG ZT-T V6 2.5 - electrical wiper problem - Page 2

Keith · 2nd November 2008, 10:07

Your may be the exception and a true fault but most so far have been the result of altertions to the cars wiring.

typically fitting aftermarket radios and the subsequent disconnection of essential live feeds to the car

Ditto for fitting and removing of car phone kits

Other are due to bodgers trying to hide faulty sat nav systems at the point of sale.

Collectivley it can take quite a while to pin point especially if intermittent.
Jules and I worked on his car recently that was doing it constantly using my T4 to eliminate ecu related issues that left him definately looking for a wiring fault which took a while but it was eventually found

Morrisman · 2nd November 2008, 12:55

Hi everyone,
Thanks for your suggestions. Things have suddenly moved into a new phase - the fault is no longer intermittent and now occurs all the time.
The wipers ( front and rear) came on again yesterday with the ignition off and the car locked. As before the only way to stop them is to turn the ignition on to position 1 ( when the wipers behave as normal in response to the wiper switch ) or remove fuse F8 in the passenger footwell. The wiper fuse in the engine compartment only disables the windscreen wipers - F8 seems to be the critical component for disabling both front and rear. However whereas on previous occasions things reverted to normal for some weeks on replacing this fuse, now the wipers ( both sets) start up again ( with ignition off ) as soon as I replace the fuse.
In response to recent comments, the car does not have a satnav , and as far as I am aware the wiring has not been altered - I have had the car for three years and this is the first time the problem has occured.
Thanks again for all your help and suggestions. There is obviously not a simple solution and since I do not have the expertise or kit for detailed electrical checks I think the time has come to call in an auto electrician. Hopefully now the problem is no longer intermittent it will be easier to diagnose? Or am I clutching at straws!!!???
- I 'll let you know how I get on.

Pete

Keith · 2nd November 2008, 13:16

If you go to an auto electrician without access to T4 or an equivalent then yes unless he knows the 75 inside out you will be clutching at straws and he will charge you for his learning time and the lack of experience could make things worse!

Go to somebody that knows what they are doing, me for example but I don't do any spannering in the winter

If you fancy the Trip Jules has a lot of experience of this problem and his rates are fair

Seriously though first I would go to your local Xpart Centre they will have T4, should know how to use it and should have the expertise to trace the problem which will probably be either be a faulty park switch (although I am not sure if that would cause the rear to go) or it will be a wiring issue somewhere

Disabling auto park on T4 may give a hint to where the problem is and would be a quick temp fix.

I have done that before when fixing a manic wash wipe problem till the damaged wire was traced.

Just be advised wiring faults if that is what you have take a long time to trace so shop around for someone with experience that does not charge £75-£100 per hour! Someone that knows the BMW E46 well would be familiar with the Rover electrics as it is 90% the same

Morrisman · 2nd November 2008, 14:26

Thanks Keith - sound advice
Pete

Moonstone · 2nd November 2008, 15:22

Quote:

Originally Posted by Morrisman

... the only way to stop them is to turn the ignition on to position 1 ( when the wipers behave as normal in response to the wiper switch ) or remove fuse F8 in the passenger footwell. The wiper fuse in the engine compartment only disables the windscreen wipers - F8 seems to be the critical component for disabling both front and rear.

According to Haynes, F8 is a fed from the ignition switch. Haynes is not always right (and it seems different to the diagram referenced by SD1too), so you should check to see it's live with the key out. Haynes' diagram doesn't include the tailgate wiper, but as it has a separate relay, this points to the BCU as the common problem - the BCU will be triggerring the relays. I don't know if a T4 could diagnose this, but you'd need one for a replacement BCU - cost is around £120 plus fitting/programming.

SD1too · 2nd November 2008, 17:02

Pete,

My owner's handbook confirms that fuse 8 (in the passenger footwell) protects the BCU, not specifically the wipers or any other circuit.

I'm now not sure why the circuit diagrams show fuses 17 & 32 feeding the BCU as part of the Wipers & washers circuit. Thanks for pointing this out Moonstone.

I suppose you could try re-seating the connectors on the BCU, just in case there's a bad connection, before calling out the cavalry.

Simon.

2nd November 2008, 17:02	#16
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: 20,416 Thanks: 1,587 Thanked 3,749 Times in 3,181 Posts	Pete, My owner's handbook confirms that fuse 8 (in the passenger footwell) protects the BCU, not specifically the wipers or any other circuit. I'm now not sure why the circuit diagrams show fuses 17 & 32 feeding the BCU as part of the Wipers & washers circuit. Thanks for pointing this out Moonstone. I suppose you could try re-seating the connectors on the BCU, just in case there's a bad connection, before calling out the cavalry. Simon. __________________ "Whatever is rightly done, however humble, is noble." Sir Henry Royce.

2nd November 2008, 10:07	#11
Keith This is my second home ZT400 Join Date: Oct 2006 Location: Ellesmere Posts: 5,948 Thanks: 0 Thanked 43 Times in 29 Posts	Your may be the exception and a true fault but most so far have been the result of altertions to the cars wiring. typically fitting aftermarket radios and the subsequent disconnection of essential live feeds to the car Ditto for fitting and removing of car phone kits Other are due to bodgers trying to hide faulty sat nav systems at the point of sale. Collectivley it can take quite a while to pin point especially if intermittent. Jules and I worked on his car recently that was doing it constantly using my T4 to eliminate ecu related issues that left him definately looking for a wiring fault which took a while but it was eventually found

2nd November 2008, 12:55	#12
Morrisman Newbie MG ZT-T 190+ Join Date: Oct 2008 Location: South Oxfordshire Posts: 4 Thanks: 0 Thanked 0 Times in 0 Posts	Hi everyone, Thanks for your suggestions. Things have suddenly moved into a new phase - the fault is no longer intermittent and now occurs all the time. The wipers ( front and rear) came on again yesterday with the ignition off and the car locked. As before the only way to stop them is to turn the ignition on to position 1 ( when the wipers behave as normal in response to the wiper switch ) or remove fuse F8 in the passenger footwell. The wiper fuse in the engine compartment only disables the windscreen wipers - F8 seems to be the critical component for disabling both front and rear. However whereas on previous occasions things reverted to normal for some weeks on replacing this fuse, now the wipers ( both sets) start up again ( with ignition off ) as soon as I replace the fuse. In response to recent comments, the car does not have a satnav , and as far as I am aware the wiring has not been altered - I have had the car for three years and this is the first time the problem has occured. Thanks again for all your help and suggestions. There is obviously not a simple solution and since I do not have the expertise or kit for detailed electrical checks I think the time has come to call in an auto electrician. Hopefully now the problem is no longer intermittent it will be easier to diagnose? Or am I clutching at straws!!!??? - I 'll let you know how I get on. Pete

2nd November 2008, 13:16	#13
Keith This is my second home ZT400 Join Date: Oct 2006 Location: Ellesmere Posts: 5,948 Thanks: 0 Thanked 43 Times in 29 Posts	If you go to an auto electrician without access to T4 or an equivalent then yes unless he knows the 75 inside out you will be clutching at straws and he will charge you for his learning time and the lack of experience could make things worse! Go to somebody that knows what they are doing, me for example but I don't do any spannering in the winter If you fancy the Trip Jules has a lot of experience of this problem and his rates are fair Seriously though first I would go to your local Xpart Centre they will have T4, should know how to use it and should have the expertise to trace the problem which will probably be either be a faulty park switch (although I am not sure if that would cause the rear to go) or it will be a wiring issue somewhere Disabling auto park on T4 may give a hint to where the problem is and would be a quick temp fix. I have done that before when fixing a manic wash wipe problem till the damaged wire was traced. Just be advised wiring faults if that is what you have take a long time to trace so shop around for someone with experience that does not charge £75-£100 per hour! Someone that knows the BMW E46 well would be familiar with the Rover electrics as it is 90% the same

2nd November 2008, 14:26	#14
Morrisman Newbie MG ZT-T 190+ Join Date: Oct 2008 Location: South Oxfordshire Posts: 4 Thanks: 0 Thanked 0 Times in 0 Posts	Thanks Keith - sound advice Pete