Check your radiator/condenser fan operation NOW
- Thread starter DanG144
- Start date
DanG144
Top Post Dawg
I do not think so, but I do not know all of the capabilities of an "obdcom" scanner.
Perhaps you can find someone in your area.
This is a partial list of VCDS owners in Florida.
http://forums.tdiclub.com/showpost.php?p=2421567&postcount=4
Perhaps you can find someone in your area.
This is a partial list of VCDS owners in Florida.
http://forums.tdiclub.com/showpost.php?p=2421567&postcount=4
weebl
Veteran Member
You might want to use it a little more often, winter included. The refrigerant contains lubricant, and not having that circulate on a regular basis can lead to premature failure of an A/C. A/C is very useful in quick defogging (you can have the heater on at the same time), and I find while I scrape the car off in the winter, I can have it on for extra electrical load to help the engine generate some heat. Seems to warm up a little quicker when I start driving.shagin'wagen said:I wish that I had the opportunity to use my AC. It was -5 and snowing all day here.But when it does finally warm up, I'll definitely check it. I think that I might have this problem, because last summer it sometimes took quite a while for it to blow cool air. Then again, I rarely use my AC and I'm perfectly happy rolling down the highway or in town with the windows down. I'll still look into it though, I like it when things work and my dad loves the AC.
DanG144
Top Post Dawg
But there is an interlock on low refrigerant pressure and another on low ambient temperature. These will prevent compressor operation below about 32F, 0C.weebl said:
Here in the South, I use my AC as a defroster whenever I can, but mine will not run below about 35 F. I know of one car on which the AC will not run below about 37F.
Dan,
Thanks for all this great info. I'm having what I think may be the onset of AC problems in my recently acquired '00 Beetle TDI. I'm not sure what to expect from it, but it seems pretty anemic until I get it up to freeway speed, and even then not all that great. From reading your papers I thought the fans might be a likely culprit.
I checked them a few minutes ago, and right away something seems weird. You state emphatically, and it seems to be confirmed by other's experience, that the low speed fans should come on any time the key is set to on, and the AC is turned on and the interior fan running. They aren't in my car. Just out of curiosity I tried starting on the engine, and low and behold then the fans then ran.
It appears that there are two distinct triggers for the fans. Would this indicate that one is not functioning as designed?
Thanks
Thanks for all this great info. I'm having what I think may be the onset of AC problems in my recently acquired '00 Beetle TDI. I'm not sure what to expect from it, but it seems pretty anemic until I get it up to freeway speed, and even then not all that great. From reading your papers I thought the fans might be a likely culprit.
I checked them a few minutes ago, and right away something seems weird. You state emphatically, and it seems to be confirmed by other's experience, that the low speed fans should come on any time the key is set to on, and the AC is turned on and the interior fan running. They aren't in my car. Just out of curiosity I tried starting on the engine, and low and behold then the fans then ran.
It appears that there are two distinct triggers for the fans. Would this indicate that one is not functioning as designed?
Thanks
DanG144
Top Post Dawg
What was the build date for your car? You can find it on the driver's door frame. Was it after May of '99?everyman said:
And do you have the standard, manual AC? (as opposed to the really fancy Climatronic?)
If you do then the fans should come on when the key is on, AC on and a cabin fan is selected. I do not think that it is a different interlock or control circuit. I suspect that one of your relays is not working until the voltage goes up from 12 or so to 14 or so after the car starts. But that is just a guess. It could also be that the fan's brushes are not making good contact and the higher voltage is needed to provide enough torque to start them rolling. Or the vibration of the running engine is letting something marginal work.
You might try giving the fans a spin by hand and see if they take off.
You might try putting a battery charger on your battery and raising the voltage to see if that makes a difference.
You might try tapping on your Fan control module (hanging under the battery), to see if that allows the relay to pick up.
If your AC is anemic until you get up to speed, then I would continue to suspect the fans are not always running when they should.
If you find out any different, please let me know. Heck, whatever you find out, let us know. I am always willing to learn.
Hey Dan,
It's a 10-99 build date. Plain Jane manual AC controls. I'll check out the rest of these suggestions tomorrow in the daylight. Hopefully I can reach this stuff in the Beetle. It all seems a bit cramped up there. Are there any caveats with throwing a charger on the battery, like something that must be disconnected first lest I fry something? I haven't got a Bentley book yet.
Regards,
Eric
It's a 10-99 build date. Plain Jane manual AC controls. I'll check out the rest of these suggestions tomorrow in the daylight. Hopefully I can reach this stuff in the Beetle. It all seems a bit cramped up there. Are there any caveats with throwing a charger on the battery, like something that must be disconnected first lest I fry something? I haven't got a Bentley book yet.
Regards,
Eric
DSL HED
Veteran Member
Is there a different testing procedure for cars with automatic transmissions? I tried doing the test listed for a manual car on my wife's 2000 Jetta, and neither fan came on with the A/C on and the fan switch set to 1. I even started it up and nothing changed. The engine was cold though, maybe that made a difference? I just want to verify both her fans are working since her car is now 9 years old. Looks like the fans are relatively cheap to buy if they are dead.
DanG144
Top Post Dawg
The New Beetle is pretty cramped, and any ALH with an auto transmission is pretty tight. You might have to take the belly pan, and even the left side cover, off on a car with an automatic transmission.
The AC and fan controls work the same on cars with manual transmissions and cars with auto transmissions. The "manual" designator in this case is used to differentiate between "manual AC" and "climatronic AC". These are the designators used in the Bentley manual.
The AC and fan controls work the same on cars with manual transmissions and cars with auto transmissions. The "manual" designator in this case is used to differentiate between "manual AC" and "climatronic AC". These are the designators used in the Bentley manual.
DanG144
Top Post Dawg
The fans should come on. There is no difference in fan and AC operation between the auto and manual transmissions.DSL HED said:
You will need to do more troubleshooting (see the links in post #1) to determine why the fans do not come on. On a car that age you are very likely to find at least two problems. I would not be surprised to find you have a bad fan or two AND a bad Fan Control Module. If you do the troubleshooting you can avoid spending $100 or so on each attempt at "Easter Egging" - replacing parts on hunches or perceived likelihood of failure.
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DSL HED
Veteran Member
Okay, thanks for the reply Dan. I thought "manual" was in reference to transmission type. I'll check out the links in the first post and see if I can figure out what's broken. I tried the test in my 2003 Jetta this morning and both fans came on without a problem. However, the PS fan is squeaking a little bit. But at least mine both came on!
DanG144
Top Post Dawg
I take no special precautions with a battery charger, except to never connect one to the car's electrical system unless a battery is present to smooth out any voltage spikes. I have even used them in the "boost start" configuration.everyman said:
It is very good to clean the 3 grounds under the battery, the main ground on the transmission bellhousing, and the battery connections every 4 years or so. Bad connections can cause extra voltage drops which play havoc with many systems on our cars.
DanG144
Top Post Dawg
One "heads up" for anyone using the troubleshooting guide for the Manual AC system.
Be sure to check the voltage from the Fan Control Module to the clutch WITH ALL ELECTRICAL CONNECTIONS MADE UP. On at least one user's car the FCM was putting out the required 9.5 volts until the normal 4 ohm electrical load from the clutch was put on the circuit. The voltage fell to zero.
I will be updating the guide sometime within a week to incorporate this lesson learned.
Be sure to check the voltage from the Fan Control Module to the clutch WITH ALL ELECTRICAL CONNECTIONS MADE UP. On at least one user's car the FCM was putting out the required 9.5 volts until the normal 4 ohm electrical load from the clutch was put on the circuit. The voltage fell to zero.
I will be updating the guide sometime within a week to incorporate this lesson learned.
mannytranny
Top Post Dawg
Thanks for the heads up.....I checked mine and found that the small fan works, but the larger one does not work. I spun the large one and it twitched a bit, which leads me to believe the issue is with the motor. Ill be disassembling it later.
wanders
Veteran Member
Thanks Dan,
Checked mine, and all is A-OK.
Checked mine, and all is A-OK.
mannytranny
Top Post Dawg
Update...I decided to try a cheapie fix and it looks like it worked....
I shot compressed air into the rear of the motor casing. Lots and lots of dust came out. I tried it and they both work 100%. I think a shot of 90 psi compressed air would be really good preventative maint for this.
I shot compressed air into the rear of the motor casing. Lots and lots of dust came out. I tried it and they both work 100%. I think a shot of 90 psi compressed air would be really good preventative maint for this.
DanG144
Top Post Dawg
Just check that they work each time you fuel up. The fixes we do are usually temporary.
DanG144
Top Post Dawg
If you have a CAN bus system, and a Climatronic, you might be able to figure out how to use the VCDS for troubleshooting.
If you have an older, manual system, I do not think it will be much help with the AC system.
Do not hesitate to ask if you have any questions.
Dan
If you have an older, manual system, I do not think it will be much help with the AC system.
Do not hesitate to ask if you have any questions.
Dan
Of course now that I have the tool to troubleshoot the A/C, it works w/o any issues. No fault codes were found ether. I did notice one thing that seemed to be a bit high. The turbo boost pressure was reading about 37 psi (2580 mbar) @ 3100 rpm (I do have a stage-2 chip tuning installed, but I did not expect that much boost).
I will try again later.
I will try again later.
DanG144
Top Post Dawg
If that is a stock maf, then that is right at the maximum possible output signal it can produce.
If it is a sustained reading, then it is probably too high for a stage 2 tune.
If it is a sustained reading, then it is probably too high for a stage 2 tune.
I finally received some faulty output. I was measuring Auto-HVAC, when the measuring blocks started to read error group not available. If you switch off the measuring block group and back onto it, it would start to get an output again. Is it the Climatronic controls that I am getting the reading from?
The Boost pressure is not a sustained reading. Should I consider replacing the stock maf with an aftermarket?
The Boost pressure is not a sustained reading. Should I consider replacing the stock maf with an aftermarket?
DanG144
Top Post Dawg
If the high boost spike is only for a second when you first get into the throttle, then it drops back and controls at a lower number then you can stick with your OEM maf. Putting on a higher span MAF requires a recode of your ECU, and perhaps your diagnostic program as well.
I think you are communicating with the climatronic unit. Is your Climatronic a Hella? There is a front panel diagnostic for the Hella, that you can do without a VCDS.
I know very little about the Cimatronic, and using the VCDS on one, but I am interested in learning.
Dan
I think you are communicating with the climatronic unit. Is your Climatronic a Hella? There is a front panel diagnostic for the Hella, that you can do without a VCDS.
I know very little about the Cimatronic, and using the VCDS on one, but I am interested in learning.
Dan
DanG144
Top Post Dawg
Rev 6 of A4 Air Conditioning troubleshooting guide
Rev 6 of the A4 May 99- MY 2005 Air Conditioning Troubleshooting guide is now located at the bottom of post #1 in this thread.
This new revision has you measure the voltage to the clutch under load.
It has a few new values in it for G65 DC voltages, to help those that cannot lay their hands on a duty cycle meter.
It has you check the G65 output earlier in the troubleshooting; this may allow you to skip the hassle of unplugging the Fan Control Module.
Critical review comments are always welcome.
Dan
Rev 6 of the A4 May 99- MY 2005 Air Conditioning Troubleshooting guide is now located at the bottom of post #1 in this thread.
This new revision has you measure the voltage to the clutch under load.
It has a few new values in it for G65 DC voltages, to help those that cannot lay their hands on a duty cycle meter.
It has you check the G65 output earlier in the troubleshooting; this may allow you to skip the hassle of unplugging the Fan Control Module.
Critical review comments are always welcome.
Dan
I did some additional trouble shooting and the only difference that I can find is the compressor load. The compressor load is much higher when the A/C is putting out cold air. It took about ten minutes before the A/C started putting out cold air. I am not sure why the compressor load would change if all the other variables stayed the same.
A/C not working – car at idle (900 RPM)
Compressor rotation: 1000 rotations per minute
Compressor Current: .82 Amps
Compressor Load: 3.5 Nm
Evaporator Temp 38 °C
Left Outlet Blower Temperature: 27 °C
Right Outlet Blower Temperature: 27 °C
Compressor Shut-Off Code: 0
Radiator Fan Activation (actual): 25.6 %
Radiator Fan Activation (spec.): 30.4 %
Engine Speed (increase): ON
A/C working – car at idle
Compressor rotation: 1000 rotations per minute
Compressor Current: .82 Amps
Compressor Load: 10 Nm
Evaporator Temp 38 °C
Left Outlet Blower Temperature: 11 °C
Right Outlet Blower Temperature: 10 °C
Compressor Shut-Off Code: 0
Radiator Fan Activation (actual): 29.6 %
Radiator Fan Activation (spec.): 35.4 %
Engine Speed (increase): ON
A/C not working – car at idle (900 RPM)
Compressor rotation: 1000 rotations per minute
Compressor Current: .82 Amps
Compressor Load: 3.5 Nm
Evaporator Temp 38 °C
Left Outlet Blower Temperature: 27 °C
Right Outlet Blower Temperature: 27 °C
Compressor Shut-Off Code: 0
Radiator Fan Activation (actual): 25.6 %
Radiator Fan Activation (spec.): 30.4 %
Engine Speed (increase): ON
A/C working – car at idle
Compressor rotation: 1000 rotations per minute
Compressor Current: .82 Amps
Compressor Load: 10 Nm
Evaporator Temp 38 °C
Left Outlet Blower Temperature: 11 °C
Right Outlet Blower Temperature: 10 °C
Compressor Shut-Off Code: 0
Radiator Fan Activation (actual): 29.6 %
Radiator Fan Activation (spec.): 35.4 %
Engine Speed (increase): ON
DanG144
Top Post Dawg
I am not familiar with the Climatronic setup. I have no experience with it.
If it uses the same compressor (and I THINK it does) as the manual AC system, then there is a mechanical compressor control system built into the compressor, the unit is replaceable, keeping the same compressor.
Look for recent posts on the subject (within the last month), maybe a reply by jcrews or joetdi? Look in TDi101, and both A4 forums.
Dan
If it uses the same compressor (and I THINK it does) as the manual AC system, then there is a mechanical compressor control system built into the compressor, the unit is replaceable, keeping the same compressor.
Look for recent posts on the subject (within the last month), maybe a reply by jcrews or joetdi? Look in TDi101, and both A4 forums.
Dan
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DanG144
Top Post Dawg
You might look at the compressor and verify the clutch is actually engaged.
And it seems very odd to me that the evaporator temperature remained constant at 38 C. That is much too hot for an evaporator.
The compressor load is likely a value calculated on compressor differential pressure (or perhaps just discharge pressure.)
Does your Auto AC module in VCDS have an OUTPUT TEST block?
That could be very informative.
And it seems very odd to me that the evaporator temperature remained constant at 38 C. That is much too hot for an evaporator.
The compressor load is likely a value calculated on compressor differential pressure (or perhaps just discharge pressure.)
Does your Auto AC module in VCDS have an OUTPUT TEST block?
That could be very informative.
Yardstick
Veteran Member
Great info here. It's too bad I didn't have this last year when my A/C quit.
I did the quick test yesterday; car on (not running), A/C button on, low fan speed (and turned on recirculate -not sure if that makes a difference in the test) and neither of my fans moved. However... I don't know that I've got enough charge in the A/C system in the first place. Does that matter in this test?
Here's the story: Last year my A/C quit on a road trip in ~110F heat. I was sitting still with the engine running when the A/C got warmer and warmer and the air got humid in the car. I found some of my old info and apparently I only had ~20psi static pressure in the system. I tried charging it with a leak detector kit and it wouldn't draw in a charge. I got some bad advice to jumper the compressor to force it to draw a charge in. It worked, but in the process the overpressure blow-off valve opened on the compressor. In the Bentley manual it says that the overpressure valve will blow off excess pressure and then close to keep from losing all of the charge. So I'm not sure what my pressures are like now, but I can put the gauges back on if I have to. It sounds like I've got fans (and maybe other systems) to troubleshoot first though.
I did the quick test yesterday; car on (not running), A/C button on, low fan speed (and turned on recirculate -not sure if that makes a difference in the test) and neither of my fans moved. However... I don't know that I've got enough charge in the A/C system in the first place. Does that matter in this test?
Here's the story: Last year my A/C quit on a road trip in ~110F heat. I was sitting still with the engine running when the A/C got warmer and warmer and the air got humid in the car. I found some of my old info and apparently I only had ~20psi static pressure in the system. I tried charging it with a leak detector kit and it wouldn't draw in a charge. I got some bad advice to jumper the compressor to force it to draw a charge in. It worked, but in the process the overpressure blow-off valve opened on the compressor. In the Bentley manual it says that the overpressure valve will blow off excess pressure and then close to keep from losing all of the charge. So I'm not sure what my pressures are like now, but I can put the gauges back on if I have to. It sounds like I've got fans (and maybe other systems) to troubleshoot first though.