Discussion in 'VW Mk4 Jetta, Golf, New Beetle, Passat TDI forum' started by almir, Jun 12, 2011.
Thank you, Almir, just finished replacing my AC coil with relative ease thanks to your write-up.
This was awesome, thanks for posting. Saved me a lot of $$ and now my wife's AC works!!
no problem guys, The best thing I like about it is that you don't have to disconnect AC compressor lines. I will just have to include the site where I got the coil from.
All the best, and I hope this will help many more
I have a four relay bypass diagram but do you have a seven relay replacement diagram?
FCM bypass el. diagram
yes I do, please print both pages and then tape them together since it was to big for my scanner
Worked out great!
VW mechanic thought it was a bad compressor and quoted around $1000 for the compressor, dryer, accumulator the evac and recharge. I figured it would be worth the time and money to try the coil first since the compressor seemed to be turning fine, it wasnt making noise and I couldnt get the clutch to engage even when by-passing. I ordered one from Polar and just finished the change out. It only took about and hour and a half and the AC is blowing as cold as ever! 2: Thanks for the post...I was just going to go without AC before I spent that kind of money!
Does any one know if this will work for a Golf/Jetta with the 2.0L gas?
My first post here!
Needed to look at the pictures and was wondering if I can use this to change the clutch on my MK4 VR6
if you check closely metal label (blue) it will tell you what is the model of your compressor google and see if your compressor is the same as on TDI 2005 MK4. Or even better go to Autozone's website type in your year and model and see what compressor model and picture pops out, then do the same for my compressor 2005 jetta tdi 1.9 BEW (engine code) see if part numbers and pictures match.
I would say compressor is compressor all it needs is something to spin it and it doesn't care if it's diesel engine or gasoline, therefore I don't think that VW would design different compressor for golf/jetta gasoline engines. So the procedure for changing the coil should be the same. Not sure about location vs alternator. Anyway try to use the same trick to use wire and tie it so that it is facing you in the best possible way.
Seems to be the same a mine, Sanden SD7V16. There are different sub models and mine is model 1216. I bought a new clutch from e-bay that's supposed to work on my compressor. I filled the compressor too fast and the clutch burnt out. It's $38 dollars on e-bay for a new one. I'll report back if everything works out.
Hello I am having a somewhat similar problem with a 2001 golf.
The clutch in my ac comp is not engaging, not even if powered directly, the coil is receiving 8.9V with engine off and 9.3V with some jumping to 11.5V with engine on and ac to LOW (climatronic). Ended last summer with the ac blowing hot air while set to 21C/70F
My question is about the FCM, is it normal for the fans to be running all the time? And the voltage on the comp coil is it ok, because I have read that it should be around 4V. What checks do you recommend to diagnose this problem?
Thank you for posting this helpful info
hi, with engine off, and AC compressor connector disconnected use ohm meter to measure resistance on the coil. If I remember a good coil should have around 3.5-4 ohms. If you are in range, then use two wires connect the ac coil connector to your battery terminals. You should see coil move in when you apply voltage and move out when you remove voltage. Fans should nor run all the time. Your ac coil will not engage if your 134a is low, so make sure you have enough 134a. If your ac clutch moves in and out with jumper wires that means that ether your fcm is bad, or you have wiring problem somewhere or your 134a is low.
I would charge it with a half of the 134a can while jumping it your compressor with wires just to get compressor moving and to pull in gas from the can faster.
Is this DIY for a BRM?
Hello. Where can you buy a new clutch pulley? Mine is starting to squeak. Any help would be appreciated!
I found that the FCM receives power from two routes. You can see voltage (and the 9.? volt figure definitely rang a bell with me) on the compressor coil output just as a side effect of the control voltages coming into the FCM. But the power to run the compressor coil (and the fans as well, I think) comes from a dedicated supply circuit originating in the power distribution box on top of the battery. This box contains several fusible links, but it also contains three regular fuses. The one nearest the passenger side (in my '01 gas Golf GLS anyway) provides the power to the FCM to run the fans and compressor clutch. Another runs the ABS and I forget what the third was for.
I found that on my car this fuse was not blown, but its plastic body (and the casing of the distribution box) had melted from the heat generated by a bad connection between the fuse and its socket. The fuse was actually plastic-welded in place. The bad connection had also eventually led to an open circuit so no A/C or fans. Plugging the fuse in the opposite way gave a temporary repair, but the bad terminal in the socket soon lost its connection again. I dismantled the distribution box, cleaned the fuse terminals and tried to crimp them shut a bit for better contact.
So far, so good, things are working.
I don't know if this is a sample defect or if the fuse holder in the distribution box is under-designed for having the circuit draw near full load (A/C plus 2 fans all on together) for long periods. It could also be that an aftermarket A/C coil draws a bit more current, enough to overheat the connection but not enough to blow the fuse.
I just went through this process on my Jetta and have a few notes for everyone to make their lives easier.
The most important thing to consider is what the root cause may have been or that there may be another issue. The clutch hub was not fully engaging on my compressor and therefore would slip and generate lots of heat once the system got up to pressure. I recommend running the system for five minutes and then cycling it off and back on to make sure that it fully engages after the pressure goes up.
The reason my clutch was slipping was not because of the shim, but rather because the hub was rusted and did not move freely enough to engage fully. This can be observed by attempting to bend the outer portion of the hub inward by hand (toward where the compressor would be when it's installed) while pressing outward on the splined inner portion. If you don't have noticeable movement there, you should replace the hub as well.
I highly recommend everyone replace the hub when doing the magnet. In my case, I believe the clutch got VERY hot because of the slipping and ultimately caused the coil to fail. You can also test the engagement by hooking the reassembled clutch to your battery to listen for a definite "click" engagement noise. Look for movement. You should see a noticeable movement every time you connect and disconnect the battery.
Good luck everyone!
I have a 2001 jetta TDI. The ac is not working. I have no resistance across the green and brown wires on the compressor clutch. I got a FCM from the junkyard and checked it against your specs. It read open across all 4 pins. My old one read the same. The driver side fan is not working when the ac is on. Do I need a new FCM or to build your Franken-FCM? I'm thinking yes. Also, does the open reading on the compressor clutch mean it is shot?
coil should have continuity from one side to the other, I think you have found your problem Just stick with my notes and you will be OK. So get a new coil if you disconnected ac compressor connector and on the compressor side you read open. Don't remember what I wrote about new FCM specs but if you already checked with my notes then you are on the right track. If you buy FCM buy a good one, stay away from the ones that are $50 or less especially because mine lasted only for 2 weeks. Also if you have my diagram for the 7 relay FCM and if really know what you are doing with electrical jobs, then go ahead and do it. Use good and thick wires like they used on fcm and you shouldn't have any problems. Mine still works.
I have a 2003 golf with ALH engine. I just finished my complete timing belt job and noticed that the pulley on my ac makes a lot of noise when I spin it by hand, as if the bearing is shot, is there a chance to replace the bearing in the main pulley? Would you know what size of bearing I would need? Otherwise my ac works very well. Thanks
The noise you hear probably is not the bearing it is the air gap of your clutch that is too close and is scraping the other side
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