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7th December 2020, 00:20 | #1 |
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Diesel aircon fan (Another one)
Hi all,
So since owning the ZT CDTI the aircon has never worked. I bridged the connector block, checked the fuses, etc, and the fan has never moved. So today I swapped over the silver to the gold resistor. Still nothing. When bridging the the little connector block, the compressor starts to run.. but no fan. So I'm wondering, will the fan not come on if the aircon needs regassing? I haven't had it done yet. Also... some cars, the aircon is disabled below a certain temperature... it was 3degrees when I was testing it. Any advice on where to go next? |
7th December 2020, 08:47 | #2 |
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With most vehicles, if there is insufficient gas pressure, then it will prevent the compressor from starting to prevent it being damaged. I would imagine that the 75 is the same.
I would suggest getting it on a vac test to see if there are any leaks (I would imagine there would be if it has never worked). Many re-gas places will do this first and most don't charge if the system does not hold a vacuum. |
7th December 2020, 08:59 | #3 | |||
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Quote:
Hi Marc. Now you have added the gold resistor in place of the silver one, have you tried the demist test, ignition to II make sure all the A/C is in the off position, then press only the demist button go to the front grill and see if the fan is running continually. If the fan is not running then you need to do more investigation, wiring, relays, maybe the PCB board is damaged.
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7th December 2020, 09:14 | #4 |
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Hi guys thanks for the replies.
The front end behind the bumper is pretty manky looking, so I'm going to replace the intercooler and condenser. I have checked all relays and fuses, which are fine,so I might just bite the bullet and replace the fan unit to. Are there any favoured brands for the 3 items? |
7th December 2020, 10:28 | #5 | |
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With a gold resistor fitted you'll most likely be wasting your time and money doing that. Arctic has given good advice (he owns a diesel too); do the "demist test". It only takes two minutes. To make diagnosis easier, I'd recommend that you book a mobile, independent self-employed specialist to check and recharge your air conditioning. There will then be no doubt about the fan's operation. Even though they'll be cheaper, don't use the Fast-Fit boys or a general garage for this work. Let us know about the demist test though Marc. Simon
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7th December 2020, 10:59 | #6 | |
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The intercooler may only need cleaning out, if its not holed in anyway no point in changing it, if you remove the intercooler make sure you add new O-rings Viton. 1 How did you get to the relay's in the fan control box ? 2 Most two speed fans last it is the silver resistor that fails, and needs changing for the gold one which you say you have done. 3 4 If the condenser is poor that would still not stop the fan from running on the low speed. Be careful purchasing condensers as some with some the brackets do not line up and you have to do a little work to sort this out, not an hard job.
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7th December 2020, 20:33 | #7 |
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Thanks for the replies guys.
Yes I have tried the demist test, and not a sausage. I haven't opened the control box, I didn't realise it was servicable. I have a day off Wednesday, so I will have a look. Regards the intercooler, it looks pretty awful, so I don't mind spending a few quid. The same goes for the condenser, the fins are almost all none existent. |
7th December 2020, 22:37 | #8 | ||
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The intercooler can be cleaned inside and out if removed from the car, it is most likely road dirt, and or black gunk from the O-rings failing at sometime. I have used these condensers before but as i say some need a little modification with the bracket lining up. https://www.ebay.co.uk/itm/CONDENSER...T/283687728162
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8th December 2020, 08:02 | #9 | |
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Thanks Marc. That strengthens the possibility that your fan isn't working which will affect the efficiency of the air conditioning.
Quote:
The relays are in the control box which you say you haven't opened. However they very rarely, if ever, fail. When you do open the box, check that it has a PCB inside as shown in Arctic's photo (it has been known for a petrol fan/control box assembly to have been installed in a diesel which won't work!). Thanks for your helpful replies so far. Simon
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8th December 2020, 23:43 | #10 |
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Thank you for all the replies so far guys, it's appreciated.
Simon, yes I did bridge the pins on the trinary switch, as you said, pins 1+4 does trigger the compressor, but pins 2 +3 didn't do anything at all. When I said relays, I meant I checked all the fuses listed in the fuse boxes. I have tomorrow off of work, so I'll find an hour 2 for some more fault finding. Arctic... I was a actually looking at that on eBay this morning and wondering if it was of decent quality. You have answered my question! |
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