Check your radiator/condenser fan operation NOW

If there's no gas in the system the clutch will not engage so unless the front bearing at the clutch is bad there's no harm in leaving it alone.

Gothmolly said:

Does anyone know if there is an AC delete option? Some kind of pulley which can be installed to keep the right belts in the right tensions? At this point the AC fix will cost more than the car is worth (counting time and money).

Click to expand...

Yes, there is a bracket and pulley available which replaces the compressor and allows the stock belt to be used.

However, it's a Dorman product and the one my son installed had a very noisy bearing after only a few thousand km. He tossed it and installed a used compressor with a good bearing instead.

2000 Beetle fans do not come on slow when Ignition on, A/C pressed, blower on 1.

- Fans work fine from rad fan sensor on both low with key off and high speeds with key on.
- All fuses are ok. S164, S180, 5,16,25
- Replaced FCM
- A/C clutch 4 ohms
Seems like wiring issue why fan don't come on low.

How much pressure is in the system (check low side)?

No pressure, fans will not come on and neither will the compressor.

20 psi on the low side. So if there is low pressure then the fans will never come on slow correct.

I can direct 12v direct to the compressor to add some R134a plus dye. Then run it for a while.

1975 Kombi said:

20 psi on the low side. So if there is low pressure then the fans will never come on slow correct.

Click to expand...

Correct. A can of refrigerant has more pressure in it than that, so if you start to charge it it WILL accept the charge (slowly; keep the can in a warm water bath as the evaporation of gas in the can will chill it and thus it may take quite a while otherwise) and the system will come on once there is a reasonable pressure in it. DO NOT invert the can (charge liquid) as there is no accumulator in front of the compressor and if you slug it with liquid and it is running it may be destroyed.

However, the system is leaking, so you need to find the leak and fix it (which means recovering the refrigerant, fixing the leak by replacing the bad component(s), replacing the dryer since you will have to open it to replace the component(s) that are defective) then pulling a hard vacuum on it and recharging by weight.

Small leaks always get larger if not repaired; they never get smaller. And NEVER use any sort of "sealer" in an A/C system -- it will seal things you do not want it to and then you'll have to rip out and replace EVERYTHING.

The plan is to add some 134a with dye until the system fires up so I can find the leak. Most likely the condenser. Oddly my 2001 Beetle TDI has a different pinout on the J293 fan control module than the Jetta or Golf (not sure on the year). I'm looking for a pinout now for the J293 for the 2001 Beetle TDI.

I have made a direct 12V supply for the A/C compressor. Fused with a on/off toggle. For testing purposes.

What is the amps for the compressor clutch? 15A

Can I add frostycool 134a or will it not mix with the 134a that is in the system now. I'm not sure I can buy a 134a can in Canada.

OK. A small amount of dye and a small amount of 134a have been added and the fans are on. Now with the system static and the high and low pressures equal what should be a rough pressure? 75psi? Engine off for a 30 mins period.

Found it. 30-40 low and 225 high when running.

Depends on the outside temp. 75psi is "in range" at reasonable temps system and car off however. You can't judge charge that way but it will definitely come on with that pressure in there.

I added a 12oz can of 134a and some dye. 30psi low and 115psi high while running and 72psi not running equal both sides. I will check for leaks over the next week.

You are still quite-materially undercharged but the system will run in that state. Note that the "at rest" pressure varies with ambient temperature (assuming everything involved is at that and not hot because the engine has been run, etc.)

I have a 2003 Jetta ALH {manual air} with no compressor clutch engagement.Fans work on low with ac on. AC cools with power at compressor to engage clutch. AC clutch engages when power is applied to t14/10 on FCM plug. I have power at both sides of high pressure switch and t14/2 I have power at both sides of ambient temperature switch but no power at t14/5
My questions are should I have power at t14/5 and or t14/3 when unpluged from FCM. And where is the F163 thermal cutout switch located and should I have power at t14/13?
thanks

sewerrat said:

I have a 2003 Jetta ALH {manual air} with no compressor clutch engagement.Fans work on low with ac on. AC cools with power at compressor to engage clutch. AC clutch engages when power is applied to t14/10 on FCM plug. I have power at both sides of high pressure switch and t14/2 I have power at both sides of ambient temperature switch but no power at t14/5
My questions are should I have power at t14/5 and or t14/3 when unpluged from FCM. And where is the F163 thermal cutout switch located and should I have power at t14/13?
thanks

Click to expand...

My failed FCM (fan control module) story from this weekend sounds pretty similar to your symptoms. You don't mention if your fans also don't work when you have the AC running with the engine running.

2002 Jetta, ALH, manual AC. I live in San Diego, and prefer to drive with windows down vs. using the AC. So, my AC doesn't get used much. A few weeks ago, I had occasion to use it, and it did not work. I had not run it for many months. I finally looked at it today and found the clutch was not engaging, and the fans weren't running. After watching the clutch for a minute, it would catch for a millisecond and turn maybe 1/3 to 1/2 turn, but that was it. Very strange.

Read the troubleshooting guide. Checked fan operation: key-on-engine-off, AC on, and both fans came on at low speed as expected. Disconnected clutch connector and checked voltage at the harness side with engine running, AC on: 9.5 V. Checked coil resistance: 5.5 ohms. I did not seek to check the voltage with the clutch connector connected, although that is suggested by the guide. I didn't want to pierce any wires and don't have the fine probes to back-probe the connector. Plugged the clutch connector back in and tried again with engine on, AC on. Same behavior. Mostly not engaging, except for a split second every 10-20 seconds. Disconnected the clutch coil again and momentarily put 12 V directly to the coil using my jump pack with the engine off, and the clutch operated fine.

Hooked up AC diagnostic gauges. Got about 80 psi static pressure on both sides. I decided to try running the AC with the clutch on outside power. Left the clutch disconnected, started the engine, turned AC on, and put 12 V to the coil from the jump pack. Compressor ran fine. Observed the high side pressure increase pretty rapidly to above 200 psi and continue rising, while the low side dropped to around 30. Interestingly, the fans now operated, at first at low speed shortly after the high side started to climb in pressure and then at high speed as the pressure climbed well above 200. Then, I guess it hit the pressure limit, and the fans cut off. Even though the compressor was still engaged because it was independently powered, the high pressure started to drop and low started to rise. Not sure why that happened with the compressor running. Anyway, the pressures would start to equalize, then the fans would kick back on, and the high would go back up and low would go back down, and it would cycle like this. Again, not sure why. Anyway, everything seemed good at this point. I did not seek to test the G35 pressure sensor since I didn't have a meter that could measure duty cycle (and the Fluke M87V mentioned in the guide is $400+ on Amazon).

So, I suspected the FCM. I happened to have a spare available on my 2003 auto-to-manual swap project that's currently a work in progress. I swapped over the FCM, and the AC was back to normal. I'm going to drop in a salvage unit when I have time to grab one. Hopefully, that's the final solution.

Edit (7/5/23): Pick-a-part FCM is in. AC is working fine.

Brett

Brett San Diego said:

My failed FCM story from this weekend sounds pretty similar to your symptoms. You don't mention if your fans also don't work when you have the AC running with the engine running.

2002 Jetta, ALH, manual AC. I live in San Diego, and prefer to drive with windows down vs. using the AC. So, my AC doesn't get used much. A few weeks ago, I had occasion to use it, and it did not work. I had not run it for many months. I finally looked at it today and found the clutch was not engaging, and the fans weren't running. After watching the clutch for a minute, it would catch for a millisecond and turn maybe 1/3 to 1/2 turn, but that was it. Very strange.

Read the troubleshooting guide. Checked fan operation: key-on-engine-off, AC on, and both fans came on at low speed as expected. Disconnected clutch connector and checked voltage at the harness side with engine running, AC on: 9.5 V. Checked coil resistance: 5.5 ohms. I did not seek to check the voltage with the clutch connector connected, although that is suggested by the guide. I didn't want to pierce any wires and don't have the fine probes to back-probe the connector. Plugged the clutch connector back in and tried again with engine on, AC on. Same behavior. Mostly not engaging, except for a split second every 10-20 seconds. Disconnected the clutch coil again and momentarily put 12 V directly to the coil using my jump pack with the engine off, and the clutch operated fine.

Hooked up AC diagnostic gauges. Got about 80 psi static pressure on both sides. I decided to try running the AC with the clutch on outside power. Left the clutch disconnected, started the engine, turned AC on, and put 12 V to the coil from the jump pack. Compressor ran fine. Observed the high side pressure increase pretty rapidly to above 200 psi and continue rising, while the low side dropped to around 30. Interestingly, the fans now operated, at first at low speed shortly after the high side started to climb in pressure and then at high speed as the pressure climbed well above 200. Then, I guess it hit the pressure limit, and the fans cut off. Even though the compressor was still engaged because it was independently powered, the high pressure started to drop and low started to rise. Not sure why that happened with the compressor running. Anyway, the pressures would start to equalize, then the fans would kick back on, and the high would go back up and low would go back down, and it would cycle like this. Again, not sure why. Anyway, everything seemed good at this point. I did not seek to test the G35 pressure sensor since I didn't have a meter that could measure duty cycle (and the Fluke M87V mentioned in the guide is $400+ on Amazon).

So, I suspected the FCM. I happened to have a spare available on my 2003 auto-to-manual swap project that's currently a work in progress. I swapped over the FCM, and the AC was back to normal. I'm going to drop in a salvage unit when I have time to grab one. Hopefully, that's the final solution.

Brett

Click to expand...

Well that’s some interesting timing on this post, the last time I started my car the compressor did the same thing, cuts in and out. The fans work though. Anyway I haven’t delved into it yet as I’m still doing suspension, so I’m awfully glad to see how it turned out for you. Now I need to find out if I can swap the FCM with the one on my 1.8T parts car... should be the same unit no?

When I did a swap of 2.0L gasser Mk4 to ALH, I left the FCM alone and it works just fine.

J_dude said:

Well that’s some interesting timing on this post, the last time I started my car the compressor did the same thing, cuts in and out. The fans work though. Anyway I haven’t delved into it yet as I’m still doing suspension, so I’m awfully glad to see how it turned out for you. Now I need to find out if I can swap the FCM with the one on my 1.8T parts car... should be the same unit no?

Click to expand...

Yes, Same for every Mk4 Golf, Beetle, Jetta. I picked a salvage FCM from a 2003 Jetta this afternoon ($16). AC runs fine, now. Out of curiosity, I just checked FCPEuro. You can get a new Febi FCM for $47. Not bad, with the lifetime warranty. Genuine VW is $280.
Brett

Just used this guide once again to solve a fan/AC issue. MUCH appreciated!

Crap, I'm back in the hot AC club after about 7 good years. My fans stopped turning slow a month back and I figured they'd failed prematurely even though they were just installed in 2015, 30k miles ago. I just paid $500 for new ones and guess what, they still aren't turning. Pressure according to the little gauge on a r134 can is about 60, a tad high but I wouldn't think enough to trigger an over pressure condition?

Am I looking at a new FC module at this point? The compressor was supposedly installed by the PO about 80k miles ago. Any idea where it hides on an ALH Beetle?

edit: Well crap^2, I just finished watching a video in which the presenter went to install a new $200 FCM, only to find out the wires to one of the pigtails were actually corroded. Great, another failure mode and both require the same amount of disassembly, and I have no garage to work in, and it's 105 out... FML.

If I pull it all apart, only to find it either is, or is not the harness, am I okay to, throw the battery in and run the car without a FCM until I either get a new pigtail or a new FCM? I now have two broken European cars. There's a lesson in there somewhere.

ericas_beetle said:

Crap, I'm back in the hot AC club after about 7 good years. My fans stopped turning slow a month back and I figured they'd failed prematurely even though they were just installed in 2015, 30k miles ago. I just paid $500 for new ones and guess what, they still aren't turning. Pressure according to the little gauge on a r134 can is about 60, a tad high but I wouldn't think enough to trigger an over pressure condition?

Am I looking at a new FC module at this point? The compressor was supposedly installed by the PO about 80k miles ago. Any idea where it hides on an ALH Beetle?

edit: Well crap^2, I just finished watching a video in which the presenter went to install a new $200 FCM, only to find out the wires to one of the pigtails were actually corroded. Great, another failure mode and both require the same amount of disassembly, and I have no garage to work in, and it's 105 out... FML.

If I pull it all apart, only to find it either is, or is not the harness, am I okay to, throw the battery in and run the car without a FCM until I either get a new pigtail or a new FCM? I now have two broken European cars. There's a lesson in there somewhere.

Click to expand...

There's a lot of missing information in your comments. Not much to go on for anyone trying to help diagnose your issue. You can drive the car as long as you want without AC. Unlikely you're damaging anything. This thread starts 70 pages ago with a complete guide on how to diagnose your non-working AC system, at least from the electical perspective. I suggest you start on page 1 of the thread. As far as the mechanical side, there must be thousands of youtube videos by now that explain the general theory of operation of an air conditioning system. I suggest going there. One easy thing to check first is if your compressor clutch is engaging. Don't know what that is? Youtube. When you've done some diagnostics and still haven't got it working again, come back with more details.

Brett

Just fixed a similar situation where the owner suspected the fan module, bought one, still no fans or AC. The AC light did not illuminate upon pushing the button.
One fan was bad but that was not the root of the problem. I believe that whoever installed the radio disconnected the harness connector on the console controls for the HVAC and either did not fully snap the connection back together or simply forgot to do so.
You got to go through the above procedure that Brett mentioned and eliminate the posibilities before shelling out money for unnecessary parts.
Definitely, do not throw out the old FCM.
And, chop the wires off the defective fans right at the motor so that you now have test leads for future fan issues.

Brett San Diego said:

This thread starts 70 pages ago with a complete guide on how to diagnose your non-working AC system

Click to expand...

Thanks for the nudge in the right direction. I had read a bunch of this thread but somehow skipped the most essential trouble shooting document. It turned out I had an intermittent connection at the 30 amp fuse and the high speed 40 amp fusible link blew sometime recently. I installed a whole new fuse box and it's doing great now.

ericas_beetle said:

Thanks for the nudge in the right direction. I had read a bunch of this thread but somehow skipped the most essential trouble shooting document. It turned out I had an intermittent connection at the 30 amp fuse and the high speed 40 amp fusible link blew sometime recently. I installed a whole new fuse box and it's doing great now.

Click to expand...

Thanks for actually getting back with the solution. Too many threads die off without resolution, and that's just not helpful. I would worry about what caused the 40 amp fuse to blow and if that problem still exists.

edit: I just re-read your post, and you said you had the fans replaced, so maybe it was one of the old fans that caused the fuse to blow.

Brett

Looking for some help with this, might be related. 2002 TDI ALH Manual AC. AC was working great, then it wasn't. The fan(s) both are trying to cycle on and off. In fact, from high to low just with the key on. AC blowing hot so I thought it was low Freon, but when I tried to charge the scale on the can was off the scale high and would not recharge. When i push the AC switch, both fans turn on high, but AC blows hot.
I checked the fuse at the top of the battery, was not blown. and that's has far as it got. Summary:

1. with key on, both fans try to cycle from high to low
2. with key on, engine running, AC switch on both fans stay on high but no AC

Any ideas? where to start?

Is the aluminum pipe near the top of the passenger side of the radiator cold to the touch when the AC is turned on and fans running? That is the return line to the compressor.
It could be you overfilled the system with refrigerant and the pressure is now too high. That can cause the fans to cycle hi / lo.

There are other reasons why the HVAC blows hot in this case even when the system is cooling the evaporator and otherwise in working order.
1 - the foam has deteriorated and blown off of the blend doors exposing gaping holes, (much needed design feature ), and not allowing you to shut off the heated air coming from the heater core.
2 - the pivot pin on the bottom of the blend door that the control lever attaches to has separated from the door and you can't put the blend door in the correct position for AC to blow out of the vents.

Either of these last two things means you have some work ahead of you to fix it.

Brett San Diego said:

edit: I just re-read your post, and you said you had the fans replaced, so maybe it was one of the old fans that caused the fuse to blow.

Click to expand...

I think the hint is in the troubleshooting doc. If low speed is not working reliably, and then high speed kicks on, it causes a much higher than normal peak current as it tries to bump start high speed from standstill. I'm going to be carrying spare fuses, and a wrench just in case moving forward, but I think that so long as slow sleed is operating normally, then it probably won't blow again.

para55a said:

I checked the fuse at the top of the battery, was not blown. and that's has far as it got. Summary:

Click to expand...

You'll probably want to take note of my experience here. If you don't have excellent connectivity on the 30amp blade fuse over the battery, then low speed won't function reliably. The fact that it isn't blown doesn't mean much. The terminals themselves are very old, and have much higher resistance than they should. There are knockoff fuse boxes on Amazon for less than 20 bucks. The one I got didn't fit perfectly but it worked and completely changed the behavior of the system. If that doesn't do it, then you might still have a fan controller issue but the fuse box is right in front of you. If it's not a problem, it soon will be. My car is a southern car, with no corrosion, but the fuse box was still effectively dead after 23 years.

I also found that the fuses in the dash had a strange tarnish on them, so I went through and wire brushed them clean. Read that document and it lists every fuse critical to A/C.

JETaah said:

Is the aluminum pipe near the top of the passenger side of the radiator cold to the touch when the AC is turned on and fans running? That is the return line to the compressor.
It could be you overfilled the system with refrigerant and the pressure is now too high. That can cause the fans to cycle hi / lo.

There are other reasons why the HVAC blows hot in this case even when the system is cooling the evaporator and otherwise in working order.
1 - the foam has deteriorated and blown off of the blend doors exposing gaping holes, (much needed design feature ), and not allowing you to shut off the heated air coming from the heater core.
2 - the pivot pin on the bottom of the blend door that the control lever attaches to has separated from the door and you can't put the blend door in the correct position for AC to blow out of the vents.

Either of these last two things means you have some work ahead of you to fix it.

DIY: How to fix air blend door MK4 TDI no cabin heat problem

DIY: How to fix air blend door MK4 TDI no cabin heat problem Problem: I was not experiencing cabin heat at any point during my commute. This was becoming a serious concern not only because I was freezing, but also because I couldn’t defrost. The coolant temp sensor said a solid 190...

forums.tdiclub.com

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Thanks You, I'll check. Ithought it was snowing in the car, but it was the dried out foam. Didnt think it would cause such a problem, but I will check in reply after work today

ericas_beetle said:

You'll probably want to take note of my experience here. If you don't have excellent connectivity on the 30amp blade fuse over the battery, then low speed won't function reliably. The fact that it isn't blown doesn't mean much. The terminals themselves are very old, and have much higher resistance than they should. There are knockoff fuse boxes on Amazon for less than 20 bucks. The one I got didn't fit perfectly but it worked and completely changed the behavior of the system. If that doesn't do it, then you might still have a fan controller issue but the fuse box is right in front of you. If it's not a problem, it soon will be. My car is a southern car, with no corrosion, but the fuse box was still effectively dead after 23 years.

I also found that the fuses in the dash had a strange tarnish on them, so I went through and wire brushed them clean. Read that document and it lists every fuse critical to A/C.

Click to expand...

Excellent! and I do appreciate your most valuable advise. Checking on the condition of teh fuses and will report back