Cruise Contol Stopped Working - Why?, 2.5 TD Saloon

[mackay1]

I've only had my car for a month and when I got it the cruise control was working - although I thought it wasn't quite as smooth in operation as my previous XM.

After a while I noticed that it was sometimes difficult to engage (often requiring 3 or 4 attempts). One time I noticed it re-engaged seemingly by itself after I had disengaged it (and I'm sure I didn't touch anything!). Last weekend on a long journey it was working OK for the first 100 miles and then for no apparent reason would no longer engage. It hasn't worked since. The light on the dashboard switch lights up OK and the speedo works perfectly (no judder) but the cruise simply refuses to engage.

The whole cruise control thing is a mystery to me so any help/suggestions would be appreciated. The only thing I can think of is dirty contacts on the cruise stalk but I haven't looked yet.

Thanks

Roy

[xmexclusive]

Hi Mackay1

From your description it sounds as though your stalk switch has broken. They are fairly flimsey and a real pain when they start to pack up. It is enough if you accidently catch the arm with your knee to break the switch because of the long lever arm. Then it gets difficult to engage/disengage and the continual trying breaks it completely. Mine in the V6 went over the weekend.
A new one costs just under £30 from Citroen.

As for the way it works. The dash switch is just an on/off switch for the whole cruise system. The lever is used to engage cruise and set/reset speed. it can also be used to disengage cruise but this is normally done by touching the brake.

Regards

XMexc

[mackay1]

Hi XMexc,

Thanks for that. I'll replace the stalk and let you know how it goes.

Best wishes

mackay1

[citroenxm]

Hi Cruisers!!

Just a point to add... My cruise is VERY temremental too on my V6 SEi 1992

I find that its a combination of knocking the auto from 4th to 3rd, then messing with the brake pedeal.

I think I have a fault somewhere, as theres a switch for the brake pedal, so when you brake it knocks it off. I find if I slip my foot off the side of the pedal so it bounces it will let the cruise work. Other times, if I knock gears 4th to 3rd (NOT kick down), then switch the system on then off it can also cause it to WORK!!.

How ever, everything I tried tonight wouldn't let it work..

Regards
citroenxm

[Lurch]

Hmm, my cruise control is also 'tempremental'!

It often disengages itself for no reason, sometimes a lot, sometimes not a lot, sometimes it re-engages straight away, sometimes it doesn't.

I have been told that my speedo head is faulty (causing the speedo to read 56mph constantly) and I'm wondering if a swap of this component will improve maters on the cruise control. If not, is it likely to be the switch?

I may buy another switch\actuator\lever doobrie as if it's not that I know someone who I can sell it to if it is unrequired so it won't be a wasted purchase.

Beginning to wonder why I've still got this car, it's a career, not a hobby!

[Craigdp]

there is a relay on XM's for the cruse control that is a common problem and I know it not to be cheap £80 a few years ago from citroen I hope this is not the problem for you guys.
A'bientot
Craig

[xmexclusive]

Hi All

Cruise on a 2.5 is a much simpler installation than on the petrol cars.
The 2.5 has fly by wire speed control as standard so the cruise switches take control of the speed signals from the ECU.
On my V6 the same electrical switches are used as the 2.5 but the cruise controls operate a vaccum system that is mechanically piggybacked on the linkage at the end of the throttle cable. I think this is the system with the expensive relay.

Regards

XMexc

[Craigdp]

I only know it to be on the petorl cars as that was the believed fault with it on my green 2.0ltr turbo
A'bientot
Craig

[mackay1]

Just realised I haven't posted a follow up to this.

I replaced the cruise stalk but this made no difference. I then had a good look at the wiring diagram from Noz's CD and decided it was probably the switch on the brake pedal (stangely the brake light / cruise switch is beneath the rubber on the pedal). I found that tapping the side of the brake pedal quite hard would sometimes make the cruise engage.

I replaced the brake pedal switch (15 minute job but the part cost £36.21 + VAT) and it's been perfect ever since.

Many thanks for the help on this one.

Roy

[rowanmoor]

I am having trouble retro-fitting cruise to my 2.5. See the last couple of posts here.

There was no live to the on/off switch. I notice from the wiring diagrams that this is also connected to the brake pedal switch - so I wonder if I have a problem in this area. When your switch was playing up, did the brake lights still work?

I have rigged up a live to the switch, and the light comes on, but it still does not work. I have checked the stalk with a multimeter, and all works correctly, and there is a 12v supply on the expected pins of the connector when the switch is on.

I am left with 3 of thoughts as to what it could be:
1) The brake switch has no 12v supply in the same way as the dash switch (depending where the break is). Would this not stop the brake lights working?
2) The brake switch is dodgy like yours.
3) I notice from the wiring diagram that there is a 9 pin black connector from the dash wiring loom to one of the engine wiring looms to connect the cruise switches etc up to the computer. I guess this could be unplugged. where is this connector on a RHD and how do I get to it to check?

Cheers,
Rowan.

This post has been edited by rowanmoor on May 27, 2006 02:44 pm

[citroenxm]

Hi rownmoor

The brake switch is one switch BUT it has two seperate contacts inside it to do the two jobs.. IE: Brakelights and cruise cancel.

The switch is dismantable.. Held on by one 8 or 10mm bolt (cant remeber which) and unclips from the pedal, and unplugs further up the pedal arm.

Open the switch and the seperate contacts can be seen. I think its the left set looking at the switch I just cleaned the contacts up, strengthed them up, so they opened up better and refitted and then IT HAS NOT REFUSED TO WORK NOW!

A joy!

Regards
citroenxm

(3.0litre V6 12valve 1992 SEi)

[rowanmoor]

Thanks citroenxm. I have checked the switch with a multimeter, and both parts of the switch are working correctly. As the brake lights work it must have power to the switch, so that rules that part of the system out as the cause of my problem.

That leaves my idea that the connector from the dash wiring loom to the engine wiring is disconnected. Where would I find it though?

Another idea - I presume there is a sensor on the clutch (the manual says that pressing the clucth will disengage CC). Where is the sensor? I couldn't see one on the pedal.

Cheers,
Rowan.

[mackay1]

Hi Rowanmoor,

Just a quick post. When my pedal switch was faulty the red light on the dash switch still illuminated and the brake lights worked OK. You are right of course - there is also a switch on the clutch somewhere but I couldn't find it either - and was hoping that wasn't the source of the problem on mine.

It sounds to me that you need to resolve the power to the dash switch before going any further as it should certainly light up when the switch is in.

I hope this helps a little.

Roy

[rowanmoor]

I have sorted the poer to the dash switch now by pulling power from another switch (demister as it is also ignition switched) - but the CC still isn't working. I am sure the break switch works having tested it with a multimeter - but given that one of the wires for the system (power to the dash switch) seems to have a break in it then I wonder weather another one in that loom does.

If I can find that connector then I can test all the pins to ensure signals are getting there. The wiring diagram I have doesn't even show a clutch switch, but if it is in any way connected to the pedal, it should go through the same connector to the engine bay.