Xantia A/C

[white exec]

Result! You got there!

[admiral51]

Yes them both working as intended was my main priority, now need to think about the A/C but think i may get the aux belt etc changed before i go for a regas as i know the compressor kicks in when doing the bridge trick

Colin

[mickthemaverick]

Well done Colin, cracked it in the end!! Now fingers crossed for the AC.!!

[admiral51]

Well another kicking from the blinkin motors again today
Everything fine yesterday, this morning only the r/h would work and only on fast when pulling the blue stat plug, nothing from the l/h one.
So replaced all relays to start with, no change.
Back to the tool box and Jim's special tool to remove the offending motor and check the power to the plug on the housing and yes 12v present when engine running and blower on and direction set to demist.
Put a direct feed from the battery to the offending motor and nothing apart from a nasty smell.
Back through my stash of old motors to find one that did want to show some life and try again.
Everything working again as it should so fingers crossed tomorrow morning it will still be working as it should.

Colin

[Rhothgar]

How disappointing that this thread should end so abruptly!

I have visions of poor Colin in an asylum somewhere wearing as the Austrians call it, an "I love myself jacket" (straightjacket)!

I once believe this was a general thread for all Xantia A/C questions and then realised it wasn't.

However, there is no reason why it should become one.

I've not tested my fans recently as I know I got them working with Colin's help some 2 years go.

So...

My clutch will not engage. I have supplied power directly to the compressor which you would think should engage the clutch, should it not?

The car sat for a few years and was finally resurrected about 3 years ago from memory. Maybe the compressor clutch is seized.

I have read through this whole post again just now so I will try the trinary switch bridging with the compressor plugged in.

When checking voltage last weekend, I was only seeing 0.6V at the compressor.

Am I right in thinking that:-

a) with the slider is set to demist from cold that the fans should kick in at low speed and the clutch should engage. (Yes I am).
b) Would the compressor not receive correct voltage if i) there is a fault code in the ECU pertaining to air con or fans or b) there is insufficient pressure in the system?

What would be a methodical process for getting this running?

a) Check and clear any fault codes
b) Switch slider to demist and check for 12V with ignition on or does car have to be running
c) If engine is warm, presumably the air con switch in the cabin would need to be depressed or will demist still actuate air con if enginer is above a certain temp?
d) Regas once everything else is checked and confirmed working ie regas only after I can get compressor clutch to actuate.

Obviously want to keep costs to a minimum until such time as the system is viable.

[GiveMeABreak]

Clutch will not engage if there is low pressure - it's a safety intervention so as not to damage the compressor, so you won't get it working on the car normally with low gas. There are also other reasons like when the evaporator is close to freezing where it will disengage the compressor.

Can't help with the other questions as any issues with previous compressors I have just had them replaced.

[xantia_v6]

Note that if supplying external power to the A/C clutch, it has an internal diode that is polarity sensitive.

[Rhothgar]

Note that if supplying external power to the A/C clutch, it has an internal diode that is polarity sensitive.

That's a concern! I think I applied polarity correctly. At least I hope I did. Do you know what that diode is internally? Worst comes to the worst I've just added another job to my list...

[Rhothgar]

Clutch will not engage if there is low pressure - it's a safety intervention so as not to damage the compressor, so you won't get it working on the car normally with low gas. There are also other reasons like when the evaporator is close to freezing where it will disengage the compressor.

Can't help with the other questions as any issues with previous compressors I have just had them replaced.

Thanks for your input Marc. I didn't understand this until last week. Just hope I've not blown the internal diode. This is the problem of playing with electronics before you fully understand a system.

[xantia_v6]

The diode is connected across the coil to prevent back EMF voltage spikes when the relay opens. I don't know if it is physically accessible for replacement.

[Rhothgar]

The diode is connected across the coil to prevent back EMF voltage spikes when the relay opens. I don't know if it is physically accessible for replacement.

Yep. Pretty sure I’ve blown it then as coil
Is now OL. Last week it was showing way over the 2.5 - 5.0’ohms it should typically be.

[Rhothgar]

Well. I actually tracked down the high resistance yesterday in the power supply to the compressor.

IC02 the brown cinch interconnection under the nearside wing has a corroded terminal in the moulded plastic so I am wondering if anyone on here has carefully 'butchered' one of those interconnections?

I pierced the wire before it entered the interconnection and got just over 12V. The nice, bright and shiny male terminal inside measured 1.5V so I suspect that the terminal is almost severed from the wire. On close inspection, it looks like the moulding around the yellow and blue wires (which go to terminal A1 and A2 respectively) is perforated and this would have allowed water in (as I have no undertray to protect the area in front of the wheel arch liner.

The easiest way to resolve this would be for me to clip the wire and solder in a new wire and connect into the wire just before where the sheathing goes under the fuse box behind the battery. I could use spade or bullet connectors to make it serviceable if I ever need to disconnect it (with a sacrificial bit of heatshrink tubing to protect the bullet join). This would, of course, be the easy and obvious solution.

However, me being me, I am wondering whether it is worth gradually dremelling the plastic away on the corner of interconnection IC02 down to the wire. Does anyone know if these interconnections are resin filled or voids internally? If there is a void, it would be still a task. I doubt that the male termination is removable. Certainly not easily. I could then rebuild the corner up using plastic weld.

Am I completely nuts?

[Rhothgar]

Apparently these Cinch interconnections are apparently accessible?

Has anyone deconstructed one? Must investigate all options before I take a dremel to it. I'm pretty sure the 'cap' is moulded to the top.

[admiral51]

Hi Roger, how is my straight jacket fitting you

There are differences in the electrical operation of the A/C between S1 and S2 so post your Vin and i am sure the great and good will post a diagram of your electrical A/C operation as the plug you have posted looks like the plug going to the infamous "Bitron Box" so called because it had Bitron written on it .
I have had a couple of Xantias both S1 and S2 and the only common way i found to bypass the system checks on the compressor was with the engine running and bridging the 2 thick ( or thin )wires on the plug going to the condensor/air dryer. Only bridge the same thickness wires as when bridging them one will set the fans running, the other will engage the clutch on the compressor, you can see and hear the click as the clutch engages as you hold the plug and bridge the pins.
Dont let the compressor run for mare than a second or so if it engages, normal operation is denied for a reason.
If it is a S2 then putting the slider to demist it should put the A/C on, memory is a bit vague but i think both fans should kick in on slow speed even if the compressor does not engage but i am probably wrong on that bit.
We sorted the fans out a couple of years ago so if you remove the brown plug on the thermostat housing with ignition on/off the fans should both kick in on slow speed for a few seconds then go full chat.
The A/C on the Xantia is a pain to fault find as it has so many checks and part of it is the fan operation.
If the fans are working as they should then you can go back to the rest of the system.

** Edit Roger if the fans are working take it for a regas, £50 or so is maybe worth the expense so they can vac the system, pressure test and maybe save you a lot of time chasing shadows **

Colin

[Rhothgar]

Hi Roger, how is my straight jacket fitting you

There are differences in the electrical operation of the A/C between S1 and S2 so post your Vin and i am sure the great and good will post a diagram of your electrical A/C operation as the plug you have posted looks like the plug going to the infamous "Bitron Box" so called because it had Bitron written on it .
I have had a couple of Xantias both S1 and S2 and the only common way i found to bypass the system checks on the compressor was with the engine running and bridging the 2 thick ( or thin )wires on the plug going to the condensor/air dryer. Only bridge the same thickness wires as when bridging them one will set the fans running, the other will engage the clutch on the compressor, you can see and hear the click as the clutch engages as you hold the plug and bridge the pins.
Dont let the compressor run for mare than a second or so if it engages, normal operation is denied for a reason.
If it is a S2 then putting the slider to demist it should put the A/C on, memory is a bit vague but i think both fans should kick in on slow speed even if the compressor does not engage but i am probably wrong on that bit.
We sorted the fans out a couple of years ago so if you remove the brown plug on the thermostat housing with ignition on/off the fans should both kick in on slow speed for a few seconds then go full chat.
The A/C on the Xantia is a pain to fault find as it has so many checks and part of it is the fan operation.
If the fans are working as they should then you can go back to the rest of the system.

** Edit Roger if the fans are working take it for a regas, £50 or so is maybe worth the expense so they can vac the system, pressure test and maybe save you a lot of time chasing shadows **

Colin

My RP is 8744 but I have the RP 8001 onwards Electrical Diagrams. Mode of operation would be good to know.

Now! I had spotted your comment earlier in the thread about the wires to the drier BUT...

Mine has 3 green wires and one white and they are ALL the same diameter so I cannot work out which the signal wires are readily.

The connector is ICO2 which sits on nearside inner wing and is not the Bitron connector which I believe is under the nearside headlight.

The connector I have identified is definitely corroded internally as I have 12V to the wire but only 1.5V to the terminal inside it. This is one fault with mine.

Once I've repaired that, I need to work out how to bridge low pressure out so it fools the ECU.

I also believe I have blown the internal diode on field coil because I didn't realise it had a diode and therefore polarity might be critical as I powered direct from the battery.

It would be great if someone had the Official Factory Air Con manual with diagnosis in. I need to check my air con manual to see if it has diagnostic flow chart in it. I think it might. Need to revisit.