Xantia hested seats - simmer setting

[CitroenCrazy]

I have 2 HDi Xantia Exclusives, one for every day use (172,000 miles) and a backup (84,000 miles). (In fact, given how little they're worth these days, I don't really understand why *everyone* doesn't have at least one !)

Anyway. now that the days have turned chilly again, I've started using the heated seat. Both cars exhibit the same fault, the seat works fine on "full boost", ie number three on the dial, but neither of the "simmer" settings work.

Has anyone sussed out where the controllers are & how they work ? I've stripped a complete front seat, so I know the controllers aren't built into the seats. Presumably they are in the centre console, beneath the control switches, but I haven't so far been motivated enough to start dismantling that area. Ideally, I'd like a known good one, or an idea of how to fix a broken one, so I'm in with the chance of restoring service over a weekend.

Any advice gratefully received

Thanks

Regards

Andrew

[DickieG]

Unless I'm very much mistaken the controllers are on the underside of the seats.

[Citroenmad]

Hi Andrew,

I can't help with your question, sorry. I would like to ask my own though: Should the heated seat switches light up? Mine don't and I suspect they are not supposed to, but wanted to check.

Andrew, were you at the X Rally last year with a silver HDI Exclusive estate? This one:


If so, I was very taken with your car, its in great condition and really gave me a taste for an Exclusive HDi Estate. Which, thanks to Richard, I eventually found.

I suspect the reason we dont all have one, or even two, is that they are not very easy to find.

[DickieG]

Should the heated seat switches light up? Mine don't and I suspect they are not supposed to, but wanted to check.

No they don't Chris.

[Citroenmad]

Should the heated seat switches light up? Mine don't and I suspect they are not supposed to, but wanted to check.

No they don't Chris.

Thanks Richard, I didn't think so as I knew you would have had them working. It would be nice if they did but its not a problem as you can feel if they are on

[CitroJim]

There is is a small ECU in the seat to control the heaters. The controller in the console is only a switch which selects different values of small resistors to tell the ECU the regulation temperature. The switch does not control the heaters directly

I would suspect the ECU has a transistor or two in there to control the simmer settings. Unfortunately I've never delved further into the ECU but would make a stab that it's not dissimilar to the blower motor controller in principle.

[CitroenCrazy]

Thanks All

Yes, the silver estate, W997 NDB is my everyday Xantia. If not the best car Citroen ever made, certainly the one most suited to daily use in 2013.......

[dnsey]

I wouldn't disagree, Jim, but suspect that it's more likely a burst-fire controller; seems a bit inefficient to just regulate the current.
If a node of the resistor network at the switch was dry-jointed, that could easily cause the fault symptoms. It might be worth swapping switches (or running jumper leads to the other seat) to check.