Its that time of year...AC problem that I can't figure out

[mrrhtuner]

Hey everybody, it's that time of year where the weather is getting warmer and our AC's are going to be in use.

On my 03 wagon which I bought a few months back in winter, the PO had identified that the clutch on the AC compressor is noisy and needs to be replaced.

I started to analyze the AC system recently and here is what I found.

-Both fans work when AC is on
-I tested the Low Pressure with a gauge I got with a Refill kit. It was in red at 70 PSI
-AC button lights up
-When I press the AC button, you feel the typical feeling in the car that the AC system starts working
-The air is not hot but about the same as if you blow on something. It's not warm but slightly below.

I was checking the fuses, Fuse #16 for the A/C clutch (10A) was fine.
I checked fuse #5 (should be 7.5A but was 10A) and it was fine also.


So as I am trying to learn more about this AC system, I have two questions.

1) Would a 10A fuse rather then the 7.5A for Fuse #5 cause me any issues (I can't imagine why)

2) Since I can't get under the car at this moment to check the AC compressor pulley, would a bad AC clutch prevent cold air from being entered into the car?

I've read up about the flaps and I don't have any foam blowing out the vents and I think I hear the flap change when I set it to AC. Yes the temp knob is set to cold.

 

[JETaah]

Did you pump up the system with refrigerant? If the system pressure is either too high or too low it disengages the compressor.

Is the ambient temp sensor working?

Can you see that the compressor clutch is engaging when A/C is ON?

Another thing is that you may have air in the system. Simply pumping up with refrigerant does not get rid of it. If the A/C has been out of service for a while it should be evacuated then filled with refrigerant. Could be that prior to you owning the car, something part was disconnected, air filled the system and then, pumped up with a refrigerant like what you are doing.

And of course the possibility of a bad compressor.

I farm out these tasks to a shop with the equipment to do the work. They can identify the leaks with dye and let you know about how long you can expect it to stay up to pressure.

 

[mrrhtuner]

Thanks JETaah.

I am unable to see the AC compressor clutch engage. I have a belly pan on and I haven't got around to taking it off. I assumed that if you can feel the performance change once the AC button is selected, that the AC clutch is engaged.

Locally, there aren't many good VW shops and I'm skeptical sending this off to have somebody work on it in fear of being overcharged for something minor or that didn't need replacing (AC compressor).

I will pull the pan off and see if the AC clutch engages. It would be noticeable to see with the A/C on and off?

 

[JETaah]

Thanks JETaah.

I will pull the pan off and see if the AC clutch engages. It would be noticeable to see with the A/C on and off?

Yes.
The center of the clutch plate on the end of the pulley will not be spinning.
If it is not spinning with the A/C engaged its easy enough to check the clutch, although it helps to have a pigtail to plug into the clutch connector on the compressor. Apply 12 VDC - (I don't remember the polarity on the coil). The clutch plate only moves towards the pulley maybe a 1/64-1/32". Or try continuity of the coil at the terminals but, that may not determine the condition of the clutch itself.

 

[1854sailor]

No need to remove the skid plate, just remove the engine cover and you can see the AC pulley from the top. Did you check the 30A fuse in the box on top of the battery? I had the same problem with our '01 Golf and it was that fuse. The fuse had not blown, but the contacts looked like they had overheated. I pulled the fuse, cleaned the contacts and closed them up a bit, cleaned the spades on the fuse and put it back together. Problem solved. I have since seen this same problem on 2 other cars.

 

[owr084]

Now, if it was your Passat having this problem, the first answer would be to check relay 384

 

[mrrhtuner]

No need to remove the skid plate, just remove the engine cover and you can see the AC pulley from the top. Did you check the 30A fuse in the box on top of the battery? I had the same problem with our '01 Golf and it was that fuse. The fuse had not blown, but the contacts looked like they had overheated. I pulled the fuse, cleaned the contacts and closed them up a bit, cleaned the spades on the fuse and put it back together. Problem solved. I have since seen this same problem on 2 other cars.

1854, are you referring to the:

S180. Coolant fan (30A).

?

Fuse arangements in fuse bracket/battery:

S162. Glow plugs (coolant) (50A).
S163. Fuel pump (FP) relay/glow plug relay (50A).
S164. Coolant fan control (FC) control module/coolant fan (40A).
S176. Relays panel interior (110A).
S177. Generator (GEN) (90 Amp.) (110A).
Generator (GEN) (120 Amp.) (150A).
S178. ABS (hydraulic pump) (30A).
S179. ABS (30A).
S180. Coolant fan (30A).​

Thanks

 

[JETaah]

If the fans are not running then the A/C will shut down due to too high pressure...unless you are moving.
Your fans are working right?

 

[mrrhtuner]

If the fans are not running then the A/C will shut down due to too high pressure...unless you are moving.
Your fans are working right?

Yes sir. When I got home at lunch today I made sure to check.

 

[1854sailor]

1854, are you referring to the:
S180. Coolant fan (30A).
?

Fuse arangements in fuse bracket/battery:
S162. Glow plugs (coolant) (50A).
S163. Fuel pump (FP) relay/glow plug relay (50A).
S164. Coolant fan control (FC) control module/coolant fan (40A).
S176. Relays panel interior (110A).
S177. Generator (GEN) (90 Amp.) (110A).
Generator (GEN) (120 Amp.) (150A).
S178. ABS (hydraulic pump) (30A).
S179. ABS (30A).
S180. Coolant fan (30A).​

Thanks

Yes, that's the one.

 

[Dimitri16V]

Use a flashlight to check whether the AC compressor is engaging
The fans running can cause the idle to change a bit , maybe that's what you mistake for compressor engagement

 

[mrrhtuner]

I just checked....the clutch doesn't engage when the AC is on

 

[Dimitri16V]

Check it for continuity
And check for voltage in the connector when you activate the AC

Most likely clutch coil is burnt

 

[maybe368]

Just looking at the low side does not tell you much. It says 70, but if the high side is also 70, the compressor is probably bad (assuming that the compressor is spinning). You really need to put a complete set of gauges on it to tell the whole story. Some parts houses have tool loan programs, like Autozone or O'Rilleys, but I don't know if that includes ac gauges. Harbor Frieght sells a cheapy. good luck...Mark

 

[1854sailor]

I just checked....the clutch doesn't engage when the AC is on

Did you check the 30A fuse? Pull it out and look at the contacts.

 

[mrrhtuner]

Yes I did, the 30A looks good. Clean and no burn or corrosion marks

 

[Windex]

Next thing I would check would be if you are getting 12v at the clutch with a test light.

 

[turbocharged798]

Odds are the clutch coil is bad...really common.

 

[meerschm]

Can you change out the coil on these compressors? I did so on my previous vehicle. made all the difference.

came with a new clutch plate, if I recall.

 

[meerschm]

our window cleaning friend is, however, correct. need to verify volts applied.

if so, and no go, could be a coil in your future.

Fine use of snap ring pliers, if I recall. I think at one point I had contacted the vendor, and they thought i was nuts to try to do the clutch with the compressor on the car. managed it ok, however. again, this was not a VW jetta, but similar equipment. just a tad difficult to get to the parts. perhaps someone who has done a clutch on an A4 can verify if it was a challenge, or easy.

 

[gquenstedt]

It can be done with the compressor still connected, but you have to unbolt it from the engine. You need a 14mm socket for the front nut, a good pair of snap ring pliers and might need a puller to get the clutch pulley off.

 

[Techzero]

I replaced mine last summer. I bought a new clutch coil on ebay. With shipping it was under $50. The ebay clutch looks similar in build to the stock, and has the correct connector. Everything else I reused. If the clutch coil is bad it will have an infinite or very high resistance. The only hard part was getting the ring clips in and having the correct ring clip pliers. A long curved type is the best. It is still working fine.

 

[stanz]

After you check voltage to coil, most likely your problem. Buy the kit with new magnet, do the job once. On an 01 beetle [gas] did it on the car unmounted with lines still connected. Did not have to evacuate or vacume. Oh the right snap ring pliars make it a breeze. Good Luck...