S

sponcom

Member
Hello All

I bought a Disco 2 4.0 V8 on LPG 2 weeks ago and generally very pleased with my first land rover. It has a couple of issues that need to be sorted but nothing major.

I do have one electrical issue with the central locking that I have not been able to find any informtion on.

Firstly the passanger side door motor locks but does not unlock and also when the car is locked the rear wiper motor motor moves a few inches as if the door lock on the rear is shorting and operating the wiper motor when it is activated. It only does this when locking.

I am not sure whether the problems are interelated or seperate. I would have put the passanger door lock issue down to a weak door lock mechanism motor but has anyone heard of the wiper moving when the central locking is activated to lock the car?

Thanks

Paul
 
Nope very strange the other issue requires a replacement lock.
And :welcome2: to the Forum
 
Thanks Discool.

Actually, slight correction to problem. The tailgate motor is operating when the car is unlocked not when it is locked. This morning I tried unplugging the tailgate motor and found that the central locking would not operate at all. It made some noises but did not lock or unlock. So the central locking and tailgate motor must share some wiring somewhere.

Very odd...
 
sponcom said:
Thanks Discool.

Actually, slight correction to problem. The tailgate motor is operating when the car is unlocked not when it is locked. This morning I tried unplugging the tailgate motor and found that the central locking would not operate at all. It made some noises but did not lock or unlock. So the central locking and tailgate motor must share some wiring somewhere.

Very odd...
Click to expand...

The outputs for rear wiper and door locks are controlled by the IDM which gets inputs from BCU. The IDM is an electronic multirelay integrated in the passenger compartment fusebox's circuit and cant be replaced as a part. If u can get hold of a known good fusebox swap it with yours to check... if the problem dissapears then that's it...if not it means it's some short circuit in a header or somewhere along the wiring(but my money is on the IDM here). When u swap the fusebox leave the ignition on position II about 5 minutes cos the IDM and the BCU must re-establish comunication....otherwise the immobiliser will kick in.
 
Many thanks for that - that sound like a good candidate for investigation. I suspected it would be some problem like that but wasn't sure of the components in the system as although I have the workshop manual have so far been unable to locate a full wiring diagram.

Cheers
 
D2 wiring is pretty complex I'm afraid, especially seeing as there are various modules which make it difficult to trace a circuit. Once a wire goes into the box of tricks anything could happen.

Just check that the wiring for the rear door has not chafed through - the place to look first is the rubber boot that carries the wires near the hinges. Often wires will split and short in there, causing all kinds of crazy things.

It is still more likely to be a fusebox or BCM issue though tbh, but always check simple stuff first!
 
sponcom said:
Many thanks for that - that sound like a good candidate for investigation. I suspected it would be some problem like that but wasn't sure of the components in the system as although I have the workshop manual have so far been unable to locate a full wiring diagram.

Cheers
Click to expand...

Read "Body controll unit > description and operation" ...there u will find the IDM descrition too(if we are speaking about RAVE, i dunno how Haynes manual is edited)
 
Thanks for your inputs all.

Worryingly I have noticed another very dangerous issue issue related to the central locking.

I was driving home this evening and my child pressed the central locking switch on the dash and the car cut out.

Fortunately I was only in a car park and not travelling at speed. I have now confirmed that unlocking the car using the central locking button will cut the vehicle out every time.

I am suspecting a problem with the BCU as this seems to be the common denominator between everything. I am expecting this is a nightmare problem to diagnose and expensive to replace the BCU meaning that ECU and keys etc. will have to be reprogrammed into any replacement.

I think I know why the it was up for sale!!
 
Imo the problem comes from the IDM/fusebox though... and when push the CDL switch it acts like when it lost communication with BCU and the immobiliser cuts the fuel. Worth a try with a known good fusebox(which includes the IDM and the alarm module aswell). If that's the problem u will not need any programming, just a new fusebox...(dont forget about the 5 minutes waiting with ighition on pos. II before u crank it)
 
I have ordered a replacement fusebox which is supposedly good and will swap it out first - Read the section on Rave you suggested and it would seem a good bet that the IDM is up the creek.

I'll post an update probably Wednesday when I've done the swap.

Thanks
 
Solved!

Replaced the fusebox and all is well so confirmed it was the IDM. Thanks for the pointer to the IDM Sierrafery -I owe you a beer!

Thanks all.
 
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