MK5 Golf GTI

All Things Mk5 => Mk5 General Area => Topic started by: ljc19630 on March 22, 2020, 11:23:13 am

Title: AC woes again - PLEASE HELP A SUICIDAL MAN :-(
Post by: ljc19630 on March 22, 2020, 11:23:13 am
Well the saga of the No AC continues. had a new AC condenser fitted when KO4 conversion done, Re Gas. Fitted new ambient temp sensor, AC pressure switch, RKX uprated solinoid valve - Still no cold AC. Took the car to local garage (ok guys) and they said that everything was doing what it should and the AC gas is full. Issue is that the fans are not coming on when AC is on LO which they should be!!! I read up on line and a common fault is that the compressor clutch that engages when AC is on has an issue with the splines rounding, hence it just spins. I took that off yesterday and the splines are fine. Checked bot 10a & 50a fuses and these are ok. Still no fans running. Spun up VCDS (again) as using the 08-HVAC diagnostic there was no faults showing, hence i used 01- Engine and initially got a P0691 fan 1 control circuit: short to gnd. That seems to point to the fan itself??? Doing my head in this and just want it sorted, but not clued up enough to determine if its the fan pack or compressor as everything else is new and been changed?? Been chatting with Pudding and his thoughts are the compressor, but only got the P0691 error yesterday  :thinking: :thinking: :thinking:- ANY HELP MUCH APPRECIATED :happy2:
Title: Re: AC woes again - PLEASE HELP A SUICIDAL MAN :-(
Post by: ljc19630 on March 22, 2020, 03:51:45 pm
Well we have another head f*ck with this now. After putting everything back together i went out foir a drive. No AC. Got home, fans not running. Left the car running for around 20 mins on my drive while i put away my hydraulic ramp. Pulled car on to garage drive, opened bonnet and f*ck me both fans running and we have Coooooooooooooold AC. Gonna do another VCDS test and see if any faults come up - WTF is going on, as last year not long after i bought the car and once the warm weather started i noticed that the Cold AC wouldnt commence untill after around 10m mins of driving, but had so much changed since then???


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Title: Re: AC woes again - PLEASE HELP A SUICIDAL MAN :-(
Post by: ljc19630 on March 22, 2020, 03:55:18 pm
Further head f*cks - turned off AC, Fans stop. Turn back on AC no Fans  - WTF Checked with VCDS using 01- Engine and 08- HVAC and no faults. I’m totally stumped now


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Title: Re: AC woes again - PLEASE HELP A SUICIDAL MAN :-(
Post by: amanda on March 22, 2020, 07:34:36 pm
Ok I am going to suggest something basic.........are you 100% sure all fans are working properly? Fan relays are prone to intermittent failure
Title: Re: AC woes again - PLEASE HELP A SUICIDAL MAN :-(
Post by: ljc19630 on March 22, 2020, 09:12:11 pm
Not 100% sure. Like I said when AC is on LO, fans not working. Today was around 11 degrees so assuming ambient temperature was ok. But after leaving the car running for around 20-25 mins the fans kicked in and Cold AC prevailed. Why the fans are not kicking in from the get go when AC is on LO is the issue????


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Title: Re: AC woes again - PLEASE HELP A SUICIDAL MAN :-(
Post by: RedSwede on March 23, 2020, 09:48:28 am
I have no idea how the Mk5 AC system works, but, this absolutely sounds like corroded/carbonised/dirty contacts on a switch, now that you say it worked once. Plus, my guess is that this is not an overly complex system, so just try to break the problem down.

Is there a relay controlling the fans? Is there a switch on the compressor clutch that feeds back when it is in? I would check that kind of thing throughout the whole system.
Title: Re: AC woes again - PLEASE HELP A SUICIDAL MAN :-(
Post by: ljc19630 on March 23, 2020, 09:56:18 am
Yeah its an odd one. I know for a fact that the fans should both spin up when the AC is on LO, but its almost like the engine needs to get to a certain hot temp before anything happens. The fact that the AC did work and blew cold, to me rules out a compressor fault and points towards a duff main fan, as this controls the small fan, but then again they BOTH worked, but now fcuk all again so far i have

had the clutch off the compressor and the splines are fine
replaced compressor solenoid for an RKX unit
replaced ambient temp sensor
replaced AC pressure switch
new condenser fitted and re gassed
Title: Re: AC woes again - PLEASE HELP A SUICIDAL MAN :-(
Post by: ljc19630 on March 23, 2020, 12:18:33 pm
Now investigating Fan Control Module 1J0919506M as read that this is also a big cause of issues and its the part that sends signals to the compressor and fans, hence could be fcuked!!!! Gonna whip out the battery & tray as believe its under there
Title: Re: AC woes again - PLEASE HELP A SUICIDAL MAN :-(
Post by: muff1991 on March 23, 2020, 12:48:24 pm
this might help:
https://forums.ross-tech.com/showthread.php?633-Tis%92-the-HVAC-Season
Title: Re: AC woes again - PLEASE HELP A SUICIDAL MAN :-(
Post by: ljc19630 on March 23, 2020, 01:09:01 pm
Thanks Shuan. So have taken out battery and tray and noticed exposed cable to the 200a SA fuse(https://uploads.tapatalk-cdn.com/20200323/504508bb93eddd2abe3d6874803d027f.jpg)
Have re sealed this.
Can anyone confirm if the fan control module is an actual plug in box
(https://uploads.tapatalk-cdn.com/20200323/ecd5c1f6ac80dda844608f0e612eadcc.jpg)


OR is it part of the large fan motor itself as I can’t find anything after taking the battery box out????

P(https://uploads.tapatalk-cdn.com/20200323/7b7593265a52bf09e9d77505812c4a34.jpg)


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Title: Re: AC woes again - PLEASE HELP A SUICIDAL MAN :-(
Post by: ljc19630 on March 24, 2020, 05:51:32 pm
Update on this
Managed to get a “loan” fan pack to try from my sons mate who has a parts business. Fitted today and made no difference. Drove back to return the pack and car takes 10 mins of driving before ANY cold AC blows. You can feel the change, as I timed it. Then when engine is turned off and the on again, AC on LO, no fans run. Takes another 10 mins before AC blows cold. I’m now angling towards the compressor being at fault as have changed every else, and tried a new fan pack


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Title: Re: AC woes again - PLEASE HELP A SUICIDAL MAN :-(
Post by: djdownes69 on April 30, 2020, 04:23:52 pm
I'm having exactly the same problem only works sometimes usually when car gets upto temperature weird, Ive only changed the pressure switch upto now, No errors when diagnostics run, Was gonna change the solenoid on the compressor but looks like that didn't solve your problem. Thinking if coolant temperature sensor would have any effect on the running of the aircon but again I'm not sure, Hope you get it sorted or I do I'll let you know  :happy2:
Title: Re: AC woes again - PLEASE HELP A SUICIDAL MAN :-(
Post by: pudding on May 02, 2020, 12:37:22 am
I didn't know the MK5 had an external fan control module?  I thought the controller was built into the larger of the two fans?  Where does the module live as I haven't seen one on mine.

With VCDS, have you run an output test on the fans?  If you run that (engine off), you will hear and see the fans start at slow speed and then ramp up to full speed. If that passes the test, you can outrule any kind of ground or fan motor issue.  The problem then lies with what ever module triggers the fans to come on when the HVAC is set to LO.

You are correct, even after a cold start, both fans should spin when you hit LO on the AC.  The fan speed will then vary depending on road speed and ambient temp.  The governance over the fans is quite complex unfortunately, and not easy to diagnose. Having said all that, you have actually seen a fan short to ground fault code, which could be intermittent, so it's likely that's the cause of your problem.  It could be an internal fault inside the fan itself though, before you start chasing bad grounds and chaffed wires.

Have you checked both fans come on?  If only one fan comes on, either the big fat fuse(s) in the engine bay fuse box has blown, or a fan motor has blown (the bigger fan usually goes first).

If you go to VW for new fans, take a mattress with you to fall onto when they give you a price.

Keep at it mate, you're getting there.  I think the fan fault code is putting you on the right path.
Title: Re: AC woes again - PLEASE HELP A SUICIDAL MAN :-(
Post by: ljc19630 on May 02, 2020, 09:36:06 am
Thanks Kev
Haven’t tried the fan test using VCDS. Do you know how that’s performed as I’ll give that a try now. I’ve got a brand new OE Sanden compressor that had only done 50 miles ready to fit once lockdown is lifted too as was worth grabbing for only £90 on eBay
Cheers
Louie


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Title: Re: AC woes again - PLEASE HELP A SUICIDAL MAN :-(
Post by: ljc19630 on May 02, 2020, 09:37:05 am
Oh and both fans definitely come on as seen that a number of times prior


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Title: Re: AC woes again - PLEASE HELP A SUICIDAL MAN :-(
Post by: amanda on May 02, 2020, 12:01:38 pm
Hmmmmm I thought there was a relay?? On the bottom of the fan unit that fails but cannot remember if that’s for air con models or climate control models
Title: Re: AC woes again - PLEASE HELP A SUICIDAL MAN :-(
Post by: ljc19630 on May 02, 2020, 01:10:07 pm
I tried a new fan pack and had exact same problem. Start car, AC set to LO - neither fan kicks in


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Title: Re: AC woes again - PLEASE HELP A SUICIDAL MAN :-(
Post by: ljc19630 on June 28, 2020, 02:14:20 pm
Hi guys
So the issue is as it was originally. Start car, set to Lo, no cold AC untill car has been driven for 10 mins. Then freezing cold AC
Tested and tested and tested and same results every time, Even when car is at running temperature, if it’s turned off, fans stop, turn back on and it takes 10 mins for AC to start blowing. I’ve got the new Sanden Compressor but just waiting for my pal to return to work on 6/7 as he’s gonna fit it as apart from that all other parts have been renewed


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Title: Re: AC woes again - PLEASE HELP A SUICIDAL MAN :-(
Post by: Octoparrot on June 28, 2020, 09:34:06 pm
Mine seems similar in that I don't start getting cold air until I've driven a mile or two, maybe it's a quirk or the car rather than a fault as I'm sure mine has had a new compressor in the past by the looks of it.
Title: Re: AC woes again - PLEASE HELP A SUICIDAL MAN :-(
Post by: ljc19630 on June 29, 2020, 07:32:03 am
Pretty sure it’s not a quirk as I know others on here that have commented and said that a should blow cold almost immediately once it’s turned on and also in Lo setting


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Title: Re: AC woes again - PLEASE HELP A SUICIDAL MAN :-(
Post by: ljc19630 on July 05, 2020, 03:39:29 pm
Hi chaps,
Well to add to this i have just discovered something. Did an oil and filter change earlier and post completion fired up the car and left it running for around 15 mins. Then went out for a 5 mile test drive. AC came on sooner, as car had been running previously. Got home checked oil level, and left the car for around 2 hours. Then needed to pop out, so started car up, AC on Low...No fans working, AC luke warm. However i then noticed that as soon as the temp gauge hit 90 degrees the AC kicked in. First time i have actually noticed this, hence what on earth could be causing the Fans not to Kick in and AC not to blow cold until the temps are up to 90 degrees? I'm going check it again later, but think i have now narrowed this down, but just need to find the link to the issue????

Cheers
Louie
Title: Re: AC woes again - PLEASE HELP A SUICIDAL MAN :-(
Post by: pudding on July 11, 2020, 01:00:56 pm
Still battling with this mate?

Just to confirm the above observations, if I start my car and flick the AC onto auto and LO, the fans come on and there's cold air within a minute or two.

You can really feel the load on the engine and the idle speed is higher.  Car feels a little more sluggish than usual to pull away from the lights.  If you can't feel this resistance, the compressor isn't running.

What fan speed are you using on the HVAC control?  When I dial it right down to LO, it automatically shuts off the air direction toggles and runs the (internal) fans at full blast.

Interesting about the 90 degree coolant observation.  There is a close relationship with the engine and HVAC controllers, and also internal/external temp sensors, which sorts out the idling speed and load sensing stuff out.  I believe there are a couple of cabin temp sensors built into, or near the air vents.  Maybe something along those lines to look into. Perhaps check the measuring blocks in VCDS to see what it thinks the internal temp is vs outside?

Probably already asked you this previously, but are there any fault codes in the HVAC or engine controllers?
Title: Re: AC woes again - PLEASE HELP A SUICIDAL MAN :-(
Post by: ljc19630 on September 23, 2020, 05:00:42 pm
Still battling with this mate?

Just to confirm the above observations, if I start my car and flick the AC onto auto and LO, the fans come on and there's cold air within a minute or two.

You can really feel the load on the engine and the idle speed is higher.  Car feels a little more sluggish than usual to pull away from the lights.  If you can't feel this resistance, the compressor isn't running.

What fan speed are you using on the HVAC control?  When I dial it right down to LO, it automatically shuts off the air direction toggles and runs the (internal) fans at full blast.

Interesting about the 90 degree coolant observation.  There is a close relationship with the engine and HVAC controllers, and also internal/external temp sensors, which sorts out the idling speed and load sensing stuff out.  I believe there are a couple of cabin temp sensors built into, or near the air vents.  Maybe something along those lines to look into. Perhaps check the measuring blocks in VCDS to see what it thinks the internal temp is vs outside?

Probably already asked you this previously, but are there any fault codes in the HVAC or engine controllers?

Hey Kev
Well you'll be pleased to know that i have FINALLY SORTED THIS ISSUE :jumpmove: :congrats: :jumpmove:. Finally got around to taking the car to my son's pal for MOT (was due in May but we had 6 months grace due to lockdown) and also got him to fit the brand new Sanden Compressor i got for only £90. Guy had fitted it and was on car for 2 days before he got rear ended and the car was written off :sad1:
The tech said it took an age to suck out the refrigerant, but apart from that all went well. I now turn on the car and within 30 seconds freezing cold AC. Could have done with this earlier in the summer, but at least now i wont get the cocking windows steaming up when its raining!!!!
I did think all along the compressor was at fault as it was so intermittent, plus had changed all sensors as well as a new condenser radiator when it was at R-Tecj last year having the KO4 conv done. So i'm a happy chappy, and food for thought for others that are having the same issues as i know a few have posted on here. Thanks for all ya help mate!!!

Cheers
Louie
Title: Re: AC woes again - PLEASE HELP A SUICIDAL MAN :-(
Post by: mikilil on June 19, 2021, 12:57:27 pm
To be honest, there is always some problem with these air conditioners, they always break down or fail. And the most important thing is that it is always very difficult to fix them.
Title: Re: AC woes again - PLEASE HELP A SUICIDAL MAN :-(
Post by: mikilil on June 19, 2021, 12:57:59 pm
To be honest, there is always some problem with these air conditioners, they always break down or fail. And the most important thing is that it is always very difficult to fix them.
Title: Re: AC woes again - PLEASE HELP A SUICIDAL MAN :-(
Post by: Arthur1 on June 23, 2021, 05:27:55 pm
Hi friend. A really unusual situation. I noticed that recently a lot of air conditioners are breaking down, even new models can work for a little more than a year and break down. I had a slightly different case, I was driving home from the office, with the air conditioner on, everything was fine. In the morning I was going to go on a visit to a neighboring city. I turn on the air conditioner, but unfortunately its air was too weak. When I arrived in the city, I turned to a local service, but the price for their services was very high. A friend to whom I went to visit advised me one site and said that there is a cheap aircon overhaul service (https://www.airconservicingsingapore.com/chemical-overhaul/). It's good that I have such a friend who can tell me what to do in case of unpleasant situations.
Title: Re: AC woes again - PLEASE HELP A SUICIDAL MAN :-(
Post by: pudding on June 25, 2021, 11:48:51 pm
Indeed.  If A/C is of little value to you (arguably the case in the UK) then if it fails, bin it off  :grin:  A shorter serpentine belt exists to delete the A/C compressor.  Junk that and the condenser, you shed some weight and the intercooler gets more unobstructed airflow  :happy2:

It's a pretty lame system even when fully working.  On the odd occasion we get 27-30 degree days in the UK, it takes a good 10-15 mins to chill the cabin down very noticeably, running at full pelt.  I haven't tried the A/C in MK7 & newer Golfs, but it was always crap in MK3 - MK6.   The A/C in my mother in law's Mercedes C class, by comparison, is literally too cold after 5 minutes.  Even Ford do a far superior A/C on their hum drum Focuses and Mondeos!