Xantia climate control not working

R

Robin Hoffmann

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Fellow Frogger
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Dec 19, 2005
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Location
Crows Nest, Queensland
Fellow enthusiasts
A couple of weeks ago the interior fan on my V6 decided to switch to full speed and couldn't be changed. After searching here on AF I changed the fan out for a spare one I had and the problem was fixed.
However, in the past few days the fan has stopped totally, as has the A/C compressor. It failed on a trip but then restarted again 30 minutes later. Next day it didn't work and hasn't worked since! I have done extensive testing and swapping of bits where I can with known working items from vehicles in my collection. All three fuses related to A/C are OK and are powered on both sides with the engine running. I swapped the fan out again and tested it in another car and it's working fine. Power from the ignition switch is being output as expected without hiccup, so I reckon the contacts in the switch are all OK. The A/C switch on the dash works OK in another vehicle, although it only controls the compressor and not the fan. Being a series 2 Xantia, the series 1 fan not working problem requiring a relay fix was apparently resolved. But I've got no power at the fan. Given that power is getting through the fuse box, it's got me stumped, and just a 'bit' frustrated.
In the fuse list in the owner's manual an A/C ECU is mentioned. Now I'm wondering if that's the problem, but I have no idea where that lives under the dash.
Any thoughts and suggestions will be very much appreciated, and thanks in advance.
Cheers, Robin
 
The extra relay added for the series 2 could have burned out??? At least its not the ignition switch.

Cheers, Ken
 
Thanks Ken. Yes, I'm glad too it's not the ignition switch. But the question is, how do I tell which relay it is? There's a whole nest of them under there.
Cheers, Robin
 
SEDRE will tell you where it is. If you don't have that application running yet, tell me what engine and transmission you have and I can produce a three page profile of circuit diagram, loom wiring and layout diagram.

Cheers, Ken
 
Fan issues can be a bit tricky to diagnose. When you're testing for power at the fan you need to remember that there won't be any there without the engine running. The ECU turns the fan on a few seconds after the car starts. So the engine needs to be running and a enough time allowed before testing. If you don't do this you will make the same mistake I did at first, and not think there was power going to the fan.

If you do have power on the big wire and connector but the fan isn't operating it could be that the connector is just not clean and tight enough. It has a fair amount of power to get through there and I have had problems there with some of mine. Also sometimes there can be a fractured solder joint at the connector.

Your initial problem sounds like the darlington pair speed controller in the fan has given up. Swapping in another fan was a good plan, but any used Xantia fan with have done a huge number of hours of operation by now.

Hope this is some help.
 
Hi Kim, thanks for that. Yes, I too was caught out once some time ago trying to test the fan without the engine running. Lesson learnt!! Yes, I have checked/cleaned the connector but I'm not getting any power down the wire. Both fans I tried worked well in another car with variable fan speed via the fan switch on the console. That's why I'm starting to wonder about the A/C ECU. Ken's suggestion re a faulty relay will be followed up. There must also be a tachymetric relay somewhere in there as well to prevent the fan from working until the engine is running? Maybe it's gone out to lunch and hasn't come back?
Thanks again and cheers, Robin
 
Ken W said:
SEDRE will tell you where it is. If you don't have that application running yet, tell me what engine and transmission you have and I can produce a three page profile of circuit diagram, loom wiring and layout diagram.

Cheers, Ken
Click to expand...
Hi Ken, thanks for your suggestion about a relay that has perhaps died. As I mentioned to Kim, I'm assuming there's a tachymetric relay in the mix somewhere to prevent the fan from working until the engine is running and maybe it's gone out to lunch.
I'm not familiar with SEDRE. Would you please tell me more? In the meantime, I'd really appreciate the circuit diagram etc. It's an ES9 J4 paired with a ZF 4HP20 auto box.
Thanks again and cheers. Robin
 
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