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16th January 2021, 17:05 | #1 |
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Rad fan and air-con not working properly
I'm in need of some advice, back on Christmas eve I had to drive through some flooded roads. I took it steady, and initially it seemed the only problem was a heat shield being knocked off the underside, and the bottom corners of the arch liners being pulled out of place. Between Christmas eve and 4th Jan I only used the car for 1 quick journey to go and help a neighbour start his Boxster, and I didn't notice anything wrong.
However, first day back to work on the 4th, I started the car to let the engine idle while I opened the gates. A I opened the gates the car just didn't sound quite right, but being 5am I didn't have time to look into it more, and put it down to not being used much for little over a week, and it being a very cold morning. But the car hasn't sounded right since, and I finally had a day off today so had a quick checkover of a few things. I noticed the cooling fan isn't coming on, at first I thought it was broken completely but it does come on every minute or so for around 15 seconds. I found a test on here, bridging 2 pins in a connector on one of the aircon pipes. bridging the 2 pins furthest apart, there was a slight delay and then the fan started up. The other test was to bridge the pins closest together, but nothing seemed to happened anywhere. When pressing the auto or econ button, there used to be a noticeable change in engine noise, and a slight drop in revs when auto was pressed, I could definitely tell audibly between air con being on and off. Now it always sounds the same, regardless of what buttons I press on the heater controls. I took off the FOS wheel arch liner so I could have a look and check the belt was still attached to the aircon pulley, it was. While I had it off I started the engine and got my son to operate the heater controls while I watch the pulleys. When he pressed demist, the air con pulley was spinning, he then pressed Auto and the outside of the pulley was spinning, but the middle was stopped. I realised it was probably because it was set to 20 and it was 6 outside, so I got him to turn it down to 16, then tried again. So demist pressed, no fan at the front, and both parts of air con pulley spinning. Auto pressed, no fan at the front, and bother parts spinning. Econ pressed and no fan at the front and outer part spinning, middle stopped. I then left it on auto for a bit and the fan at the front started up for a few seconds, then went off, came back on a minute or so later, etc I fitted a gold resistor about 5 or 6 years ago, but I'm guessing the flood water may have killed this? Hopefully solve that issue with a new resistor. What I need some advice on is the aircon. As far as I can tell, the pulley is doing what it should when on auto/demist/econ. So what could be the problem cause no drop in revs, no change of engine sound? And what exactly does it mean when there's no change when bridging the pins on the 'Trinary switch'? Sorry its a bit of a rambling post but its a bit hard to explain the engine sounding different in a post on here. I did try to do a video, but without a video of how it used to be it's a bit pointless. All I can think of is the flood water possibly caused a leak in the air con system, and its lost the gas or something? |
16th January 2021, 18:04 | #2 |
I really should get out more.......
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I am on my second gold resistor - first one lasted 5 and a half years. So yours may have failed.
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17th January 2021, 11:50 | #3 |
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It's clear that one of the issues is failure of the radiator fan's low speed system. In trying to operate the aircon, you've effectively run the basic low speed test. The stahdard way to do this is to invoke aircon operation by pressing the demist button. Aircon operation requires the low speed fan to coole the condenser (mounted in front of the engine radiator). If the low speed doesn't run, the aircon system will overheat and trip on the emergency cooling (high speed fan). This runs for a few seconds until the gas pressure is reduced to normal. This cycle repeats until aircon operation is switched off. The fix for this is a replacee,nt low speed resistor. You can source these from traders, electronics outlets and eBay.
From your description, there may well be an unrelated problem with the engine control system. This may be a consequence of driving through flood water. TC |
17th January 2021, 21:04 | #4 | ||
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Quote:
From what you've described I don't suspect a fault with your air conditioning. When the compressor engages (both parts of the pulley spinning) it's normal for the engine revs to drop slightly. As you change the temperature display inside the car, the compressor may stop and start at different settings. This is normal. As T-Cut says though, it sounds as if your resistor has failed. Quote:
Simon
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18th January 2021, 11:17 | #5 |
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Thanks for the replies. I'd assumed it probably would be the resistor at fault for the radiator fan fault, but I hadn't heard of anyone having to replace the gold resistor before. And I was hoping I might find some suggestions for the other issue before doing the resistor, so anything that needs doing with the bumper off can be done at the same time.
As for the engine revs, it did used to drop slightly when turning on the aircon, but now there's no change in revs, and it always sounds like it used to with the aircon on, even with the heater panel turned off completely. I can't be sure of wire colours, I think when the fan came on it was yellow/grey, and black that was bridged. And I think the others were just red and black, and there was no change or anything. I'm sure I read somewhere that you should be able to hear a click as the compressor engages for the air con, but when you select air con, and can see the pulley start spinning, there's no audible click or anything. |
18th January 2021, 13:31 | #6 | |||
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Quote:
One or two have "exploded" probably due to water seeping into the cable entry. Arctic always encourages the use of waterproof heatshrink (or equivalent). Quote:
Don't bridge the red/black & black red because if your air con. is low on gas you might cause expensive compressor damage. Quote:
Are you certain that your air conditioning was fully charged and working before? Simon
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18th January 2021, 19:04 | #7 |
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20th January 2021, 23:34 | #8 | ||
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Quote:
Quote:
I'll have to invest in another multimeter, I can't seem to find mine. I can't say 100% that the air con was working as in, providing cooled air, as it's been so cold lately that just fresh air from outside was as cold if not colder than the air con. However, up until this point the engine revs did drop slightly and there was a change in engine noise when the air con was running. I've ordered a new resistor for the fan, not sure when I'll get time to fit it though, but once this is fitted I'll at least know that part of it is (hopefully) sorted. |
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21st January 2021, 09:35 | #9 | |
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Quote:
Simon
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6th February 2021, 02:51 | #10 |
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I fitted a new gold resistor today so the low speed is now working on the fan. Once the bumper was removed it was immediately clear why it had failed, 1 of the wires/terminals had completely corroded off!
The radiator behind the fan looks worse for wear, missing a lot of fins, and the intercooler (I think that's what it is, along the bottom at the front...) is also missing some but not as bad as the radiator higher up. Air con isn't working, despite the compressor appearing to engage, and it still just doesn't sound right. I think I'll have to try and find a local air con specialist to come and have a look at it. Video of engine noise hear, but its rubbish as it was done on my phone: https://www.youtube.com/watch?v=eWbnXmR-3E4 Last edited by bikerdude666; 6th February 2021 at 02:59.. |
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