Xantia Air cond diagrams and Fan problem

Clogzz · Post by **Clogzz** » 11 Mar 2008, 11:44

The maps as in Haynes are for the difference in the addition of a relay to operate the blower.
The air-conditioned cars always have the transistor-driven blower without resistor.

The Bitron is in the under-bonnet fuse box, or under the passenger’s side headlamp, assuming that you’re in a right-hand-drive country, see pictures in the bucket.
The Bitron won’t be faulty in a way that affects the blower.

juraj · Post by **juraj** » 11 Mar 2008, 12:56

thanks cloggz,

appreciate it lots, but will wait till weekend before i can investigate and report if anything is worth reporting, hehe

juraj · Post by **juraj** » 18 Mar 2008, 12:29

update:

tried two different boards, one had no operation at all, other caused the fan to run at all times regardless of switch position at a fairly low speed,

i replaced the transistors on one board only to get : run at all times regardless of switch position at a fairly low speed,

the transistors a PNP, thus the signal to them must be high to cause them to be off, and low to cause them to be on, my signal is a constant 4V odd regardless of switch position, 4v might explain the low speed. Looking at a diagram of the AC system from clogzz clearly shows that the signal to the transistors comes from the AC computer or bitron computer. The switch output is supplied to the computer. So I am assuming either the switch is faulty or the computer is faulty - in which case this seems a little silly to me as if the computer fails you don't get a guarantee of simple fan operation,

Clogzz · Post by **Clogzz** » 18 Mar 2008, 13:12

Maybe try moving the speed slider quickly through its entire range several times to dislodge any dust causing dead spots, like clearing static from audio volume controls.
If that doesn’t help, squirting WD 40 into the slider may help.
If not, then it’s the climate ECU’s turn.

juraj · Post by **juraj** » 18 Mar 2008, 14:21

thanks clogzzy ill give it a go, i am plannin gto remove the switch to see if there is anything obvious there,

juraj · Post by **juraj** » 25 Mar 2008, 01:55

oh my gooood!!!

not only have i just watched the passion of the christ but i took out the fan switch and it is ok, giving very reasonable readings and all looks to be ok,

so i went out in the sleet and rain to have quick look at the bitron computer, took out the headlight only to find that the bumper and bumper support need removing!!!! i cant beleive they mounted a computer in such a stupidly inaccesible place!!! what were they thinking? maybe they got the man who designed the cx electrics back in for a drunken re-union and let him place the bitron where ever he wanted to, there is so much room all over the engie bay or under the dash to mount it instead!!

also bit silly mounting a computer out there in the weather like that, anyway i dont know if i have the energy to go round the breakers and trying computer after computer to see if mine is faulty,

ok thanks for all the help so far guys

bye

j

Clogzz · Post by **Clogzz** » 25 Mar 2008, 12:52

The Bitron under the headlamp operates the engine cooling fans, and doesn’t affect the blower, so you won’t need to explore in that area.
The climate control ECU is inside the dash, somewhere to the right of the glove box:

http://www.frenchcarforum.co.uk/forum/v ... c&start=30

http://www.frenchcarforum.co.uk/forum/v ... c&start=45

juraj · Post by **juraj** » 25 Mar 2008, 13:14

thanks again clogzzy

now that makes more sense, i thought the bitron was the climate control ecu,

bye

ps by the way do you know if the a/c ecu is the same in some peugeots, as when i was at the breakers/wreckers there was a peugeot in there that had exactly the same blower fan in it with same transistor board, even the wiring loom leading to the transistor board was identical, same plug same wire colours - trouble is i didn't know where the a/c computer was then!

bye

Clogzz · Post by **Clogzz** » 25 Mar 2008, 15:16

Clocking up an unnecessary post to tell you that I don’t know about interchangeability with Peugeots.

There probably will be in some models of the same vintage.
You would first need to see if all the controls are identical.
Then pull the board out to compare it with yours.
The picture posted above is actually from a Peugeot.