Xantia Estate rear wiper

[JSladen]

Hi,

I've been having issues with the rear wiper on my S2 (1998, 1.9TD) estate firstly becoming intermittent, and now not doing anything what so ever.

I've checked the blue relay that is part of the wiper motor assembly, and that has been re-soldered and looks good. I've also checked all the cables at the boot door joint, and they are all ok there, no cable fractures that I can find.

When metering out the cables I can't find a 12v feed reaching the back for the wiper - does anyone know if there is a joint somewhere that might be a good target, or which relay that feed might come from? I've already check Fuse F28 (which is listed as being the rear wiper, and the washer pump) which is fine.

If anyone has any ideas I would very much appreciate hearing them!

Cheers

[sparksie]

Hi

Can't offer any Xantia specific advice, but you should almost certainly have a permanent 12V, for the self park.
Most cars also have a switched 12V, from either a relay, or directly from the switch. Just to confuse, some are switched on the ground.
The stalk switch is not made of good stuff, so may well be a problem, but I don't think that would interrupt the permanent 12V, unless it's a "flip-flop" switch. If it's one of those, it should send the power out on one of two cables, depending on switch position. It's not likely to have burned out both contacts together.
I've bought the dvd for this, but haven't had time to install it yet, so I can't say what setup you should have.
You say the fuse is intact, but have you checked there's power there?

[RichardW]

The wiring diagram is here: rear wiper circuit kindly posted by CitroJim when I was having trouble with mine. There should be 12V on connection no 8 at the relay (item 5052 in that diag) - easy to spot as it has two wires connected together and the other goes to the gearbox - and they're red IIRC. Note the internals of the gearbox are wrong on that diag, as if you read it carefully you will see that the diagram implies a direct short to earth from F28 all the time the wiper is parked The usual problem with this unit is that water gets in to the gear box and seizes it up. Had this on mine, but then that was followed up by the power supply contact in the box breaking off causing a short to earth. I got it work, but had to cut the earth pin off inside the box, which means it doesn't do intermittent anymore!

[sparksie]

Thanks RichardW

As you say, something very odd about the ground connection. I suspect pin5 on the gearbox should go to pin7 on the motor, though I imagine this would ordinarily be an internal connection, with no wiring needed.
There are two fuses in question. Fuse 28 is the one for the wiper itself and fuse 24 supplies power to the stalk. If fuse 24 goes, none of the wipers will work and, since the OP made no mention of this, we can probably discount it.
The diagram shows no joints in the feed from the fusebox to pin 8 on the wiper relay, so the lack of an ignition controlled 12V on pin 8 seems the most relevant clue here.
Assuming the ignition was on when JSladen was taking his measurements and assuming there is actually power at fuse 28, then it follows there's a break in the cable and the most likely place for this is in the bellows at the tailgate hinge!
All assuming there are no further errors in the diagram, of course!
You can test this by running a temporary (fused!) feed from B+ to pin 8 on the relay. If the wiper works properly with the temporary feed in place, you've proved there is a break in the cable and you need to identify it and redo it.
Happy hunting

[JSladen]

Hi Guys, Thank you for taking the time to respond.

That diagram should come in handy, I'll print off a copy so I can have a look later while I'm at work. I can see that fault in the diagram you mention, if it really was like that then it wouldn't work for very long at all!

I suspect that some bits missing from the diagram, as it's my understanding that on an S2, the ignition drives a relay which feeds the fuseboard, rather than a direct feed, to stop the barrel burning out from extended use.

I've also tested a known good stalk and that makes no difference to the rear wiper, so I very much doubt that it is the stalk. The front wipers and both washers work fine, as does the rear demist, which also discounts F24 from being the issue.

I've metered out the 4 relevant cables at the point inside the rear pillar, so before the tailgate hinge, and I had no 12v feeds present there either, so unusually, it's not that fault!

I'm suspecting that somewhere there is a joint in that loom, even though one isn't shown on the wiring diagram, which has become separated, or else the join where the split for the washers heads off.

I've got a switched 12v in the boot already so I'll give it a go jumpering it from there to prove the motor is still happy. Beyond that it sounds like I need to pull out the fuse box and chase the cables all the way...

[sparksie]

Hi
How can you be sure you don't have a broken wire in the bellows? The sleeve will not usually break until a long time after the core!
A separated connector will usually not go intermittent before stopping, but a broken core almost always will.
With old fashioned cabling you could check for this by attempting to stretch the cables. Due to the elasticity of the sleeve, the broken cable would stretch noticeably, compared to its intact neighbours.
Sadly, with mdern hateful thinwall stuff, this can no longer be relied on to find broken cables. There simply isn't enough "give" in the sleeve to be easily noticed. You could try switching on the wiper and playing with the wires where they pass through the bellows, opening and closing the tailgate, etc.
If it moves at all, even a fraction of an inch, you've proved you're looking for a disguised broken cable.
If you have access to the wires, inboard from the tailgate, and can identify the correct one, you can test for power by piercing the outer sleeve with a sharp needle and metering the needle. Cover it with amalgamating tape afterwards.
However, given the age of the car (minimum 10yrs?) and the fact that the tailgate on an estate moves through a much bigger arc than any other door, it might be worth just redoing the whole loom at the bellows, as a safety matter. Thinwall cable is nowhere near as good at resisting repeated flexing as conventional cabling and estate hatches put them through a tough test.
This may only be the start of a slow breakdown of the whole tailgate loom, which is very frustrating if you deal with it one-by-one, not to mention the risk of broken, or nearly broken, cables becoming hot, or shorting to ground, or worse still, shorting to other cables which may not be able to carry sufficient current to blow the fuse! Ok, I know, worst case scenario, but some people are that unlucky!

[JSladen]

I've metered the cables from the wiper motor to the bit inside the rear pillar after they've passed through the hinge - that bit is all OK

[sparksie]

Ok, you're ahead of me, so.
Afraid you're going to have to follow the cable, or just replace it with a new one (probably easier) all the way back to the fusebox.
Good luck with it and please don't forget to let us know how you solve it in the end.
You've most likely been unlucky and got a car with a soldered joint where a cable reel ran out and a new one was started. These can fracture and give the symptoms you describe and, once again, thin-wall cable is more susceptible than traditional automotive flex.
I don't know of any manufacturer that keeps accurate records of all these "unauthorised" joints, so I doubt whether you'll be able to identify any suspects without actually pulling the loom apart.
If you do end up running a new wire, dont forget to cut and insulate the ends of the old one. You never know what mischief the faulty one might cause if left...

[JSladen]

Sorted.

There is indeed a cable joint - it's behind the rear LHS light cluster. The cable loom comes all the way down the pillar from the hinge, and drops into the space behind the cluster, where there is a connector linking it onto another loom, which then goes back up, and travels forward just below the rear side windows, and then drops down to the floor where the rear seats are.

Once that was fixed i then discovered that the boot locked sensor (which is in the same loom, along with the rear demist) wasn't working right, so time to dismantle the boot door again. Luckily just the clip slipped so the sensor was loose. Stuck it back on, and cable tied it up, and all happy again.

[sparksie]

Fantastic!
Thanks for the info., which will prove invaluable to the next sufferer of that problem.
Totally different setup on the hatch. All the looms come down the O/S on those. (Or at least, they do on mine!)
Haven't had to investigate the wiper,yet, but tracked all the lighting, so I could do a proper job of fitting a trailer socket. Still have to put relays in it, but that's a job for a warm, relaxed Saturday morning, sometime!
Well done for finding it and thanks for telling us!