Hi cmacedo

On the V6 there is a black plastic cover clipped onto the front of the large black ECU box in the engine compartment. Remove this cover and you will find some relays. The cruise ECU is the large one nearest the engine and usually has a silver case. The large black ECU box can be found roughly centrally on top the chassis/front wing to the left if you are standing at the front of the car looking at the engine. See Jan's photo below silver ECU case with light blue printing including a diagram of the pin numbering on the connector.

You will see from the wiring diagram that DerekW posted that the cruise switch has two different lights. There is general back lighting as in all XM front seat switches. The back lighting only comes on when the car driving lights are switched on. The other light is an orange LED in the switch used to indicate when the cruise control has power. If the switch plug has a good earth and 12 volts from Fuse 2 and the LED does not light up then either the switch contacts or the LED or its resistor are defective. The LED can be checked by applying 12 volts to the switch terminals.

John

The cruise control relay should be one of those 4 behind the left hand headlight.
John, are you referring to the item in this photo? If so, it's the cruise control ECU.

It's the silver one on the right with the blue writing on it.

John

I have edited my posting above to provide a reference to Jan's excellent photo of the relays on the front of the engine compartment ECU box. Just for completeness I believe the other relays are:

Black relay on the left - Bitron multi-relay for the fuel pump (on most earlier XM's this relay has a Brown case). The wiring diagram and contact pinning are usually moulded into the top of this relay.

Purple relay in the middle - ABS safety relay. A simple relay for the later types of ABS (Teves & Teves 20) so ORG 6810 onwards and will not be present on earlier Bendix ABS fitted XM's. The only exception to this was Mk2 V6 Manual XM's which continued to be fitted with Bendix ABS after ORG 6810 so will be without this relay.

Silver relay box on the right - Cruise control ECU for XM's fitted with Vacuum cruise control equipment. Not fitted to 2.5's as these have an electronic cruise control operated by the main engine ECU.

Regards

John

Thought I might mention here that I replaced the CC ECU last year as this proved to be faulty. The most unlikely part to fry you would think. Found out in the end after testing everything else

Hi Paul and Jan

Thanks for the comments and corrections, much appreciated. I have edited my original post to get things right.

John

Hi everybody
I disconncted the CC ECU plug and sprayed contact cleaner, stills off. What can be wrong with it? is possible to find the problem? Whats the pink (mine is green) for?
Had another issue; water expansion is leaking, its ungluing in half. Used a soldering iron and melted both halves togheter, is this sopposed to give problems in the future? do I need to buy a new one?

cheers from Brazil

Note the rust getting out of expansion

sounds like time to give the cooling system a good flush out and then add a good flushing compound (as used by auto-repairers rather than the general store stuff, more agressive) and run the engine for a couple hundred miles to let it do it's stuff. Then flush again and maybe repeat if still bad. Then refill with clean water and anti-freeze/corrosion mix to suite your environs.

Only thing here though, if there's a lot of rust in the system, the top steel pipe in the vee (or both) may be on the way to failure at some point. You might be able to fix them up with a little creative welding/brazing if they're not too bad. one of mine went on the curve near where the heater hoses connect to, but I was able to get good replacements of a scrapper locally.

Water pump was next thing to fail though, directly afterwards.

ciao
Dave

Dave

Guess what; I´ve already replace both pipes, they're so bad I just used a band-aid for a few days when the pipes were on back order. The pic from the very beginning of the history, now cooling system is flushed and running on fresh Mobil green anti freeze

Now the suspension don´t stay leveled overnight as did 10 days ago, and when in traffic light lowers back, what´s happening? any help? thanks

Obviously hydraulic fluid is leaking back to the tank from the rear suspension units. There are three possible culprits; the brake valve, the height corrector, and the suspension units themselves.

Best way to locate the leaky item is to disconnect the return hoses at the top of the reservoir and check with the suspension in the normal position and the engine running. The occasional drop of fluid from a pipe is OK but a dribble is too much.

Derek

Derek

can you tell me where are the 3 items located? do you have pictures of them? will inspect all anyway. Whats the level of chalenge doing that? Thanks