Mechanic friend replaced AC Compressor clutch wont engage

Abishop

Active member
Joined
Mar 23, 2010
Location
Illinois
TDI
97 Passat TDI, B4, 5 speed, 250M+
I will sound completely stupid here. I am not a grease monkey. I truly have trouble remembering one part from another... I ask lots of questions to figure out what is wrong with my car and fortunately have a couple of mechanics at my disposal that are honest and talented. Unfortunately the one who recently put in my AC compressor is not computer literate so it is up to me to try to ask the question he needs so he can get my car running.
Please bear with me if my "lingo" is not right on. I am terribly right brained and I do the best I can to inturpret "car talk"
I needed an AC compressor. It was so bad I had my car towed to the mechanic for fear of it shaking itself loose and crashing into everything else around it. I had previously had other pulleys and such changed out and this was the most expensive but I fear most necessary part of all...
He has installed the compressor. He has gotten freon into it till the pressure switch(is that the term to use?) engaged... he tells me the clutch will not engage. he fears it is a relay but is not familiar enough with VW's to know where it is.
Can you help us to trouble shoot?
my first question from him is where is the relay for the AC compressor?
 

Abishop

Active member
Joined
Mar 23, 2010
Location
Illinois
TDI
97 Passat TDI, B4, 5 speed, 250M+
Hi Dan, I'm sorry I thought the car specs showed up somewhere as default. it is a 97 Passat TDI.
 

Abishop

Active member
Joined
Mar 23, 2010
Location
Illinois
TDI
97 Passat TDI, B4, 5 speed, 250M+
I looked at your link. How do I know if it is A4 or such? where do I look on the car?
I was having squealing when I bought the car 4 years ago... it progressively got worse until after I replaced the idler pulley and the ... I believe, the alternator pulley (and alt. belt). Then the slightly intolerable squealing turned to unbearable squealing when AC turned to on and OMG what is that rattle/squeal? when AC was off. It was so bad I parked it. It has sat for a few months because I had gotten a quote from a local garage of around 1M to fix it and they always low ball me. So I looked up my friend who always worked on my other vehicles and asked him if he could do it. he said get the parts and it might be $50. So, I waited till he had a window of time open. . . OH also with all the things I've had done to it over the years the check engine light has never shut off... maybe that is another issue?
Thanks for any help you can offer
 

DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
Your car is not an A4, so I do not think my links or knowledge will help you much.

MOGolf has posted several times about a problematic relay in some Passats. I do not know if yours is in the year range or not.

I don't have any knowledge or reference material that can help you. Sorry.
Dan
 

alphaseinor

TDI Innovator, Gone but Not Forgotten
Joined
Jul 30, 2006
Location
Denton, TX
TDI
'03 Jetta TDI 780,000 miles (totaled out), 01 Audi TT 225 Quattro 230,000 Miles (runs great!), 00 Cabreetle Beetle dash, ALH & MK4 harness Swap
first things first:

are you getting voltage to the compressor?
if yes, then somethings wrong with the compressor
if no then something isn't supplying voltage to the compressor

it's been a long time since I've troubleshot the 97's electrical system, but IIRC it's got two different feeds to the fan control relay. one is on the high pressure switch, and the other is direct.

If you don't have enough freon in the system, you won't have voltage for the high pressure switch,
if the fuse to the high pressure switch is blown, then you won't have voltage to the fan control relay.
if the high pressure switch is bad, then it may or may not send voltage.

without these two feeds, your compressor won't run... then of course you've got the fan control relay.

unfortunately, this is probably the extent of my knowledge at the moment, don't have the schematic in front of me...
 

Abishop

Active member
Joined
Mar 23, 2010
Location
Illinois
TDI
97 Passat TDI, B4, 5 speed, 250M+
I spoke with the mechanic. He seems to understand and have checked out all this. the only thing he has not checked is to see if the compressor is bad (since I bought it new - he made assumptions). He said the clutch came apart when he pulled the old compressor... or it had come apart at some point... his comment had to do with thinking some relay or fuse may have gotten blown out in all this. Is there a schematic of relay/fuse locations I can get ahold of? He said all the fuses he has checked to known parts of the car seem to be in order. He seems to think the relay and possibly the fuse to the compressor are someplace hard to find. He is not so familiar with VW's or at least not familiar with how things look on my car. He is asking for a diagram... is there one? Thank you!!
 

alphaseinor

TDI Innovator, Gone but Not Forgotten
Joined
Jul 30, 2006
Location
Denton, TX
TDI
'03 Jetta TDI 780,000 miles (totaled out), 01 Audi TT 225 Quattro 230,000 Miles (runs great!), 00 Cabreetle Beetle dash, ALH & MK4 harness Swap
I don't have one at this time, but the bentley manual, or ondemand, or alldata will have the schematic.
 

Abishop

Active member
Joined
Mar 23, 2010
Location
Illinois
TDI
97 Passat TDI, B4, 5 speed, 250M+
Thank you for your help. He bypassed something or another and got it running. This enabled him to get more freon into it and the pressure switch kicked in. He said he had already put a can and a half and had assumed that should have been plenty... Whoo hooo! I can drive my WV again! If only I had windows that rolled down in back!
 

mpgscott

Member
Joined
Jun 17, 2010
Location
oldmeldrum
TDI
Leon 110 SX and A3 105 SE
Sorry to jump in on this but my compressor is getting voltage but the clutch is not engaging. Is it common for the clutch motor to sieze anyone got any experience? System has plenty gas as i am assuming i wouldnt get voltage at the compressor if not.

Operating the switch on the dash switches the feed to the compressor on and off.

Any advice? car in question is a 2004 A3 1.9tdi

Cheers
Mark
 

DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
It is common for the clutch coil to fail. Check the resistance of it. It should be 4 ohms. It can be replaced for less than 1/10th the cost of replacing the compressor.
And it is easily done at home.
 

Dimitri16V

Top Post Dawg
Joined
Jan 30, 2005
Location
DE
TDI
01 Golf, 04 Golf
what's with the VW AC system ? every year now , all we get is AC problems
 

mpgscott

Member
Joined
Jun 17, 2010
Location
oldmeldrum
TDI
Leon 110 SX and A3 105 SE
It is common for the clutch coil to fail. Check the resistance of it. It should be 4 ohms. It can be replaced for less than 1/10th the cost of replacing the compressor.
And it is easily done at home.
Thanks for the response, any idea of part numbers for the clutch coil? Is there a How2 on it at all? Any suggestions very much appretiated.

Cheers
 

DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
http://forums.tdiclub.com/showpost.php?p=2995992&postcount=8 for some details on ordering.

Quite often you can find a good clutch coil on a bad compressor, and get it for free.

I do not know of a how-to, but it is pretty straight forward. I have three compressors in the shop to play with right now, and intend to do a how to one day. Just always something of a higher pririty.

I suspect that on most cars you do not even have to remove the serpentine belt. Just use a spanner to hold the clutch plate still , remove the center nut, and the whole center plate assembly, then the coil mounting screw, install the new one and reverse the process.
 

gquenstedt

Veteran Member
Joined
May 26, 2006
Location
San Antonio, TX
TDI
'06, '03 x 2, '00
http://forums.tdiclub.com/showpost.php?p=2995992&postcount=8 for some details on ordering.


I suspect that on most cars you do not even have to remove the serpentine belt. Just use a spanner to hold the clutch plate still , remove the center nut, and the whole center plate assembly, then the coil mounting screw, install the new one and reverse the process.
On the A4 you have to unbolt the compressor but leave the hoses connected. Remove the nut from the shaft then the center plate comes off, then you need c-clip plyers and you take off a clip. Then use a puller NOT PUSHING against the compressor shaft and pull off the pulley. Then remove another c-clip and the coil comes off. Not quite as easy as you make it sound above...
 
Top