weird fans

john alexander · Post by **john alexander** » 06 Dec 2006, 20:33

Hi .After changing my goosed a/c comp and getting it regassed , oops xantia 1.9td 1996. a/c engineer says one iv'e just fitted has a faulty clutch and there is no power going to the comp. When i disconnect the brown plug on the thermostat housing both fans run at low speed then the offside one stops as the near side goes to high speed . Any ideas Guys regards john.

alan s · Post by **alan s** » 06 Dec 2006, 21:57

Sounds more like you have one fan working and the head pressure increasing on the compressor which then throws the high pressure safety section of the LP/HP switch on top of the receiver dryer, which if is the case means the compressor is working.
If you're not getting power to the "compressor" it won't work due to the fact that the only power that goes to the compressor, goes to the clutch, so no power = no clutch = no compressor.
The brown wire you've disconnected is the one to the engine temperature sensor.
Get him to firstly test the HP/LP switch and then I'd reckon you may need to check the fan motors.....nice job!!

http://www.frenchcarforum.co.uk/forum/v ... hp?t=10752

Can't speak for over your way, but out here, a set of Xantia fans goes around A$1100 I believe and a rebuild about A$100, so worthy of considering if necessary.

Alan S

john alexander · Post by **john alexander** » 07 Dec 2006, 00:10

Hi should clarify a bit this is with the ignition on but not the engine running. regards john.

alan s · Post by **alan s** » 07 Dec 2006, 00:31

I think you're giving yourself a few false impressions. I had a Xantia that when we bought it, the fans operated all the time. I found this same terminal disconnected. When I disconnected he Bitron relay in the process of troubleshooting it, the fans stopped instead of going full bore. If you're going to test the clutch for the compressor, I think you need to do it with everything connected as there are a few safety controls built into these systems that can make weird things happen.
If you have got no power to the clutch, then it needs to be established why and it definitely has little to do with the actual compressor; more likely the switch I mentioned above.
If the compressor didn't chop in, how did this guy charge it? Drop charge no doubt, but most I've seen done these days are done with the compressor hooked up and running to verify the charge quantity if nothing else.
If he's hit it with too much gas, the HP side of the switch may have taken over and dropped the compressor out of the circuit. This also makes the fans go full blatt as it also chops power to the Bi-tron I think you'll find.

Alan S

Clogzz · Post by **Clogzz** » 07 Dec 2006, 14:06

this is with the ignition on but not the engine running

Looks like there are two separate faults here, an air conditioning fault, and a fan speed fault.
Both fans always have to run at the same speed.
You have a high speed fault, causing only one fan to run at the high speed.
Since both work at the low speed, I would suspect a relay, or fuse, or wiring.
You’re not likely to ever need the high speed.
If you unplug the connector on the dryer bottle, the air conditioning cannot operate the fans, and their operation is then only controlled by the brown sensor going to the Bitron.
The high-speed fault is not related to the compressor fault when the engine is not running; but when it does run with the compressor running too, then it goes as per Alan’s explanations.

Map here:
http://www.frenchcarforum.co.uk/forum/v ... hp?t=17012

john alexander · Post by **john alexander** » 07 Dec 2006, 20:16

hi when i tried to supply power to the compressor ,i think i picked the wrong end of the connection so who knows what i've done. john.

alan s · Post by **alan s** » 07 Dec 2006, 21:18

Shouldn't cause too many problems providing you didn't leave it there for too long.
It should just be one wire that goes to +
When slapped onto the + terminal, just a distinct click is all you'd hear. At that stage pull the wire off the terminal and iot should click again as it releases.

Alan S

john alexander · Post by **john alexander** » 07 Dec 2006, 23:00

Hi alan I meant the wire back to the loom . john.