Citroen XM Forum

LOL. I knew we could count on you, Dean...

Some asked somewhere about the beam pattern of the later LHD headlights (the ones without internal lenses). I changed the bulbs tonight, and took a few pictures.
I thought the headlights were OK, but we will be doing a bit more night driving this winter, so a bit more light won't hurt.

The original bulbs: The improvement with the new bulbs is greater than this photo shows, I should have locked the camera settings. The addition of the high beam lights: Low beam up against a wall: High beam up against a wall:

I've done the same car-park/long-throw tests. I think you could open up the coverage laterally a bit to open up the horizontal spread. This shows up particularly on the main beam hotspot against the far wall. On main beam the bright area should approximate to the width of the car - i.e. the main beams should project perpendicular and parallel from the front of the car. If you get this right, the dip beam spread will be right.

I'm impressed with the evenness of your dip coverage. With the same LHD units and high quality bulbs, I never managed to achieve this, but got a couple of very bright pools of dip beam in front of the car.

I woke up one morning and thought to myself... "What this XM really needs is:... More relays!"

No actually, I thought that Daytime Running Lights (DRL) would be an improvement. Silver is not the most visible colour and I have found myself increasingly driving with the headlights or fog lights on in the daytime. This is OK but remembering to turn them on and OFF is a hassle, and I really get bugged by the dot matrix and trip computer displays being dimmed in the daytime.

Scandinavian-market XMs had DRL as standard, and perusal of the wiring diagrams and parts lists shows that (at least for later cars) only the FA harness was changed and 2 relays added to provide the feature. It would have been nice to find a Scandinavian FA harness, but I have not seen any for sale...

So I decided to do it myself, on the assumption that all of the required connections are available at or near the the 23N connector between the FA and AP harnesses just behind the LH headlight.

To add a bit of originality to the project, I decided to use the fog lights rather than the headlights for DRL, as I would rather save wear and tear on the super-bright (but limited life) headlight bulbs.

The circuit is based on the factory DRL design, substituting the foglamp circuit for the dipped headlight. A slight complication is that (unlike the headlights) there is no fog light fuse downstream of the 23N connector, so an extra fuse was necessary. This was (elegantly I think) located in the usually vacant F7 position in the engine fusebox which already has one end connected to the battery and is adjacent to the 23N connector.

Before describing the modification, a bit of explanation of the original wiring is needed, as it can be a little confusing:
The sidelight switch feeds power directly to F11 (F4 on earlier cars) which goes on to control the dimming of the digitall displayes (trip computer dot matrix and radio displays). For all other side, tail ind instrument bulbs, the power is routed to the front of the car through connector 23N (9), and immediately looped back through another pin (11) on the same connector before going to the side light, tail light and instrument illumination fuses and then on to the bulbs themselves (for the sidelights going through yet another pin on connector 23N (13)) .

The reason for this tortuous routing is to allow for the easy addition of DRL, by "simply" changing the FA harness, as one of the DRL relays must break the loop at 23N, to isolate the side/tail lights from the digital display dimming function. Because it is upstream of the fuses the wiring for this loop is much heavier than would be justified by the nominal load.
The DRL control uses 2 relays:

The first has the function of turning on the side lights and tail lights (without dimming the digital displays) when the ignition is switched on. It disconnects the circuit from the side light switch and connects it to the fused battery supply. The relay coil return path is via the starter motor solenoid, which means that the DRL are extinguished while the engine is cranking, saving 15A of battery drain. Note that the ignition and start circuits were already routed to connector 23N for this purpose.

The second relay connects the fog light circuit to the sidelight circuit when the sidelight switch if off (providing DRL function). When the sidelights are switched on, the fog lights are controlled by the fog light switch as normal.

The fog lights can be switched off by turning on the sidelight switch, but there is no way to switch off the side/tail lights with the ignition on unless the fuse F7 is pulled.

Because the (non-Scandinavian) FA harness does not actually have the wires for DRL (and the wires are moulded into the connectors), it is neccessary to identify cut and splice the 5 affected wires in the AP harness just before the 23N connector. The factory DRL installation fits the 2 relays at the RH end of the slam panel, but as all the connections are at the LH end, I decided to fit a twin relay pack on that side.

Tidied up a little...

It all seems to work as designed, now to find something useful to do.

BTW, can anyone identify the spare wire with a single connector lurking behind the LH headlight, it seems to disappear beside the radiator?

I believe that wire is part of the factory origional cruise control circuit....

furriegurrie wrote:I believe that wire is part of the factory origional cruise control circuit....

Interesting... I have found it now on the wiring diagrams, it is the wire between the starter inhibit relay and the cruise inhibit relay, neither of which are fitted with manual transmission (even with working cruise control).

Not much to report. The car has mostly stayed in the garage out of reach of any salt grit that may be spread when snow is expected.

A couple of minor maintenance jobs have been completed: The O-ring on the HP pump outlet has been replaced to cure a slight leakage, and the exterior temperature sensor has been replaced, as it was beginning to be optimistic.

I see that I have a very minor weepage from the HP hose that runs from the regulator to the subframe. A bit of research shows that part number 5270gs is unique to ES9 engined cars, is very prone to weeping, and is of course NFP. I think that the problem is that the collars on the rubber to steel junctions were not sufficiently crimped at the factory, as the hose appears to be in very good condition.

Any thoughts on how to tighten the crimping on the existing hose (preferably without special equipment)? How about cutting off the collar and replacing with some sort of (heavy duty) hose clamp?
Failing that I suppose I will have to trust a local hydraulic company to replace the hose (and get the angle correct).

Is that the pipe that runs around the accumulator sphere, Mike?

David Hallworth wrote:Is that the pipe that runs around the accumulator sphere, Mike?

Yes, the power steering pipe is just below it, making it tricky to see which one is leaking.

The exterior temperature sensor I fitted is reading about 10 degrees too low. Before I complain to the vendor, can anyone point me at a resistance graph for this sensor? I know that the same part is used on all PSA cars.