Xantia Heated Rear Window and Blower failure

[davewithington]

I had a gig on Tuesday night, my '97 series 1 Xantia was outside the pub.

Loaded up with PA and saxes and got in, start up and switch on both HRW and blower, as the car was covered in frost. Nothing happened, no power to either.

I only live a mile from this particular venue, so as I could see reasonably well, we drove home. Next couple of days have been clean and bright, so no real problems driving, plenty of flow from ram effect.

Today, in the garage, find a relay, uncover the wiring under the steering column ready to patch in a relay to cure the well known problem

But.......looking at the brown plug, on wire had already been cut, and linked to the red wire from the black plug, which seems to be permanently live. Current was still flowing through the ignition switch contacts, so I fitted a relay, reinstating the cut back wire from the brown plug.

Tried it, nothing worked. The relay is firing, but there's only 0.73 of a volt coming through the brown plug, as opposed to 13ish. OK, obviously been a problem in the past and the brown plug has lost its volts. So, i put the feed to the relay back on the black plug where it was. AH, partial success, the HRW kicks in but the blower does blow. And, I noticed a strong smell of frying wiring together with a light smoke haze under the bonnet, I switched of right sharpish!

I can't quite get my head round this at the moment, so I've shut up the garage and I jave a large whisky by my side.

Any thought? Is it usual for the brown plug to loose it's feed?

[Stickyfinger]

One thought, go out and disconnect the battery

[davewithington]

Done that

several times....

[Stickyfinger]

Good Lad, do not want to see a "I Set fire to my Garage" thread

[Zelandeth]

This has echoes of "why the heck is my cooling fan cycling on and off only when the ignition is off?!?" Especially as I'd taken the relays out!

Does the feed for this come through the infamous under-radiator loom?

Without schematics in front of me it's hard to theorise. From what I've seen though, when Xantia electrics decide to play up, they can do some really odd things.

[CitroJim]

Without schematics in front of me it's hard to theorise. From what I've seen though, when Xantia electrics decide to play up, they can do some really odd things.

That's true

Dave, any wiring diagrams you feel you might need, please let me know and I'll do my best to provide...

It may take a few days though, if that's OK?

[ekjdm14]

I wonder if it's possible that the blower motor has failed/shorted & that's what caused the smoke haze (possibly out of the scuttle/air inlet rather than underbonnet?)

Especially as the HRW seemed to work OK. Not sure on the Brown plug losing it's power though, perhaps Zel is onto something with the under-rad loom too?

[davewithington]

The blower had a brief reawakening on Friday, but soon stopped working again. I think there are two problems here - the historical fault when someone moved the feed from the brown plug and piggybacked to another cable, and the total loss of both HRW and blower, which points to the well known problem with the ignition switch.

The haze under the bonnet only happened when I fitted the relay to the existing wiring.

My guess is that the cable which was being used as a feed was OK when going through the ignition switch, but fitting the relay allowed more current to be pulled and overloaded the feed wire, hence the haze.

I need to fix the original problem of the feed to the brown plug going missing. The fact that I'm getting less than a volt from it does match with a high resistance joint. This is what I need to find.....

So, I'll need some wiring diagrams and location of the under radiator loom.

Jim, are the diagrams on Citroen Service?

[CitroJim]

Jim, are the diagrams on Citroen Service?

If you pay for them Dave I believe they might be but I can do them for a lot less...

So I give you the right ones can you let me have your car's RP number please?

[xantia_v6]

I don't think service.citroen or doc backup have any Xantia mk1 diagrams, they start with mk2. Paper or microfiche only I think.

[davewithington]

Jim, ORGA number is 7543

[CitroJim]

Jim, ORGA number is 7543

Excellent... I'll dig out the necessary ASAP Dave

[davewithington]

Thanks Jim

Don't rush on my account, I'm short of time to investigate now for a while

[davewithington]

Right.

I have restored power to the HRW and blower circuit, and the HRW works as it should, but.... still nothig from the blower.

Isn't there something which fails, and cuts out the blower motor?

[CitroJim]

Excellent Dave

That's a good start! This thread should help you resolve all blower issues...

viewtopic.php?f=19&t=24786

Any questions arising, come straight back...

One thing I'd do first is to look at the brown 4-way plug that takes supplies and speed control to the blower and firstly check for a good healthy 12V on the thick red and black wires with the ignition on and engine running...

Then, if it seems OK, check the plug is making good contact with the corresponding spades on the blower itself. That plug can be notorious for developing high resistances and killing the blower... Look for melt and scorch marks around the thick red and black connections...