Electrical Gremlins

[Jan-hendrik]

Hmmm. I'd try replacing the coolant temperature control unit Almost as easy as pulling plugs from different components. I'd guess it's a failed control unit and not a short circuit.

To find out what is (inter)connected where and how you need the diagrams and the knowledge on how to read them. Even if you can do that, writing up a troubleshooting guide, well, that won't be easy and takes time.

If I were you and still had some love for the vehicle, I'd take the car to a dealer for a computer diagnostics test or approach a member of the forum with a Lexia.

Or, if that is not practical, get hold of key components, such as the ECU I suggested you replace, and go down that road.

I do hope you get to the bottom of this probably easy to fix problem :-)

Jan

[nightmare]

QUOTE (Jan-hendrik @ May 19, 2012 02:36 pm) 

Hmmm. I'd try replacing the coolant temperature control unit  Almost as easy as pulling plugs from different components. I'd guess it's a failed control unit and not a short circuit.

To find out what is (inter)connected where and how you need the diagrams and the knowledge on how to read them. Even if you can do that, writing up a troubleshooting guide, well, that won't be easy and takes time.

If I were you and still had some love for the vehicle, I'd take the car to a dealer for a computer diagnostics test or approach a member of the forum with a Lexia.

Or, if that is not practical, get hold of key components, such as the ECU I suggested you replace, and go down that road.

I do hope you get to the bottom of this probably easy to fix problem :-)

Jan

Where is the coolant temperature control unit?

[Jan-hendrik]

It's under the glove box.

[nightmare]

All I can see under the glove box is the central locking control and the alarm ECU.
According to haynes manual it has a BLACK 15 pin plug connector and I can't see anything like that.

P.S. mine is right hand drive.
My nearest citroen dealer is in Glasgow 100 miles away. but that looks like I'm going to have to get to them.
IF they still have a lexia and the knowledge of the XM that is.

This post has been edited by nightmare on May 21, 2012 01:56 pm

[Jan-hendrik]

This is the Bitron, with the pink stripe. Where exactly it resides someone else here may be able to confirm. My XM is LHD and I have not had to replace the Bitron unit. I had been assured it was under the glove box. I apologize if I gave out false information. The picture seems to indicate the control unit is mounted right in back of the heater / aircon unit (back meaning facing the rear of the vehicle). The centre console.

Most members here are RHD vehicle owners. I'm sure someone will come along soon

This post has been edited by Jan-hendrik on May 21, 2012 02:45 pm

[nightmare]

Thanks Jan At least NOW I know what I'm looking for.

[nightmare]

Does anyone know where the coolant temp control unit is on a RHD XM 2.5 TD?


Update
=====

This morning after starting the engine and running it for a while and testing different circuits with a meter at the fuse box I turned the ignition off and the cooling fans didn't cut in.

Now when I turn ignition on there are no dash warning lights apart from battery and glow plug lights. Left hand DOT Matrix not working.

With engine running the rev counter is not working nor are any of the guages or the left hand DOT Matrix display.

HELP!

P.S.

Without an "accurate" wiring diagram showing the wire colours and the locations of the different parts in the circuit I am no good at electrical faults.
Haynes shows the wiring diagrams in general for the entire range of XM's both S1 and S2.
The trouble is these are not specific to a particular model or year and we all know the electrical system "Evolved" during the course of production.

[nightmare]

UPDATE

The reverse lights and passenger side indexed door mirror also dont work!
Checked fuse and bulbs. OK.

It's begining to look like a short in fuse 23's circuit somewhere.

[techmanagain]

For the reverse light, I wold look for a short or broken wire in amongst the ones going through the convoluted rubber tube on the body at the top of the rear
boot door. The indexing mirror on the passenger side only operates with the ignition on and the gear lever in reverse. Have you checked this?

[nightmare]

Thanks techmanagain.
YES I know this is part of an ongoing fault.

[nightmare]

Hi Everyone,

Its fixed

It turned out that fuse 23 is a SHUNT not a fuse.So is 22.

Some idiot put a 15amp fuse in it and that was causing all the problems.
The fuse couldn't handle the load that was put on it in winter with everything turned on. It didn't blow it but it did make it very hot and these hot to cold cycles had the effect of increasing the resistance in the fuse and causing it to corrode, it was this resistance causing the faults, even the lack of reverse lights.

I only found out about the "shunt" when I got hold of an XM owner's handbook from EBAY.
HJB doesn't mention them apart from to say

"fuses 22/23_______________transit shunt (supply cut off)"

Whatever thats supposed to mean

I have now replaced it with a proper "shunt". Looks like a fuse but the link is much thicker to handle the current.

On the plus side I've now got a nice new "valeo" ignition switch as a spare.

On the down side I've now got to replace the front wheel bearings because they sound awfull now after six months standing still. I had a feeling that a wheel bearing was on its way out before Christmas and now I know.

Thanks for all the help/advise.

This post has been edited by nightmare on June 19, 2012 11:14 pm

[Jan-hendrik]

Congratulations!

A page from the workshop manual:

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Seems meaningless.

Do it differently then.


Sorry I did not get this to you earlier!

This post has been edited by Jan-hendrik on June 20, 2012 12:16 am

[xmexclusive]

Hi Nightmare

Glad you finally tracked it down.
According to the owners manuals the revised fuse box with shunt was not fitted until the 1996 model year.
The change was made to protect the batteries on new cars during delivery and dealer storage.
It seems that the residual current drain on an XM in storage can damage or kill even a new correctly rated battery.
Very surprised that a car as early as yours has this type of fuse board.
Will check out my troublesome XM next time I visit its storage location.

John

[citroenxm]

Nightmare,

Look forward to meeting you at ICCR! Nice work and patience, your persistance is wel deserved!

Were hoping to be there on the Fri, Sat and possibly sunday.. not sure on the sunday yet.

Its looking like I may not have an XM ready to come either... :-(

[nightmare]

Looking forward to meeting you as well, will hopefully be there fri-sun with a caravan .