VW Forum banner

1 - 16 of 16 Posts

·
Registered
Joined
·
1 Posts
Discussion Starter #1 (Edited)
A/C stopped working, took it into a shop and everything is working fine but the A/C clutch isn't getting any power. The shop was an A/C specialist not a VW so they didn't have a wiring diagram. Is there a relay anyone knows of before I have to bring it to a VW shop(45 mins away).
 

·
Registered
Joined
·
7 Posts
A/C stopped working, took it into a shop and everything is working fine but the A/C clutch isn't getting any power. The shop was an A/C specialist not a VW so they didn't have a wiring diagram. Is there a relay anyone knows of before I have to bring it to a VW shop(45 mins away).
Does the secondary cooling fan come on when you turn on the ac? There's no relay. There's a pressure switch which controls both clutch and a fan. The switch is by firewall (passanger's side). There's 4 pin when you remove the connector. Two for fan and two for clutch. You need R134 to trigger the pressure switch. Make sure you have 134 in the system. If the system is charged and clutch doesn't kick in, most probably the pressure switch. You can check the voltage by disconnecting the clutch wiring by compressor and turn on the ac, you should get 12VAD. Make sure you also have 12VDC at pressure switch connector. Pressure switch is in series with ac clutch. First check the voltage at pressure switch. Remove connector from switch, with volt meter connect one test lead to negative and the other lead to the pins (not the switch side) one at a time, make sure the key is on, ac and blower switch is on. You should get 12 VDC from 2 of the pins and zero from the other two.

Here's the pressure switch
 

·
Registered
Joined
·
3 Posts
Hi Teal,

Saw the post and am trying to isolate issue on A/C on 2000 New Beetle I just picked up in a trade.

PO had it charged last year and it sounded like it worked - then stopped - usually this would mean refrig leaked out. So, starting there I connected test and fill hoses and put in a can of 134a to see if clutch started cycling - it didn't but I noticed the engine would drop in rpm every 5 sec or so (and, I was getting 8.8V cycling up to 11.5 in time with this (meter may have been too slow to see the full 12V). - but clutch was not engaging - no clicking noise, either.

I hate troubleshooting with cans of refrig ... I'll test the low pressure switch tomorrow - your post seemed to indicate that power flowed to low pressure switch and if switch senses above set pressure then power from two terminals is passed by the switch to the other two and thence to both the clutch and to the fan?

Any idea what the "cycling" is about? My gauge set showed more than enough pressure on the low side (60 psi), but nothing on high side at all (assume because compressor no turning) ....

Thanks!
 

·
Registered
Joined
·
82 Posts
ive got a similar problem to stephenson. But i am only getting 8v at the clutch. Does this mean that the pressure switch is bad, or there isn't enough 134? I'll check the voltage at the pressure switch next.
 

·
Registered
Joined
·
82 Posts
ok, just checked the pressure switch. Its not a 4 pin connector, but a 3. I was able to get 12V out of one of the pins from the harness. As soon as i plugged the harness back in, the a/c fan kicked in. I just want to make sure that im just low on 134 before i go and take the car in for a recharge or if i can add it myself. I have a manifold set for a/c, but if the compressor doesn't kick in, how are you guys adding 134. seems like mine is taking any on from the can.

Sorry for all the questions and for stealing away from the thread, but i feel like my issue is so similar.
 

·
Registered
Joined
·
8 Posts
My 2001 jetta's AC stopped working suddenly.
Everything seems fine, 92 psi on the low side ( compressor clutch does not engage)
No 12 V to the clutch. the high side pressure switch has three terminals, no 4. When I unplug the coolant fan(s) stop, but I don't hear the clutch working. How does the high side pressure switch work ? Does it turn on the fans in parallel with the clutch signal ?
P
 

·
Registered
Joined
·
52 Posts
Jeeze all these issues with cooling fans, A/c blowing warm air, a/c clutch not engaging... well im with all you guys. My a/c is blowing warm air, clutch is not engaging, replaced my a/c relay, pressure switch, fan control module, a/c condensor and radiator. My larger of the 2 fans does not come on, ever, and my smaller of the 2 fans comes on instantly and stays on the entire time and then runs 10 minutes after my car is shut off. I am almost to the point where i will take it to a VW specialist and bite the bullet and pay, but dont really have that kind of money. lets try n figure this out!!!
 

·
Premium Member
Joined
·
4,477 Posts
Jeeze all these issues with cooling fans, A/c blowing warm air, a/c clutch not engaging... well im with all you guys. My a/c is blowing warm air, clutch is not engaging, replaced my a/c relay, pressure switch, fan control module, a/c condensor and radiator. My larger of the 2 fans does not come on, ever, and my smaller of the 2 fans comes on instantly and stays on the entire time and then runs 10 minutes after my car is shut off. I am almost to the point where i will take it to a VW specialist and bite the bullet and pay, but dont really have that kind of money. lets try n figure this out!!!
Check strip fuses on top of fuse box, the smallest one (is a 40A) which should be like 3 from the left is the one that controls your fans.

If that is good, what year is your car? VW switched to a really shitty fan design in 2003 and most people with your issue swap in radiator fans/AC condenser fans from a 2000-2002 model and have no issues with it.
 

·
Registered
Joined
·
4 Posts
Similair/related A/C issues

So last fall my whole A/C system was working but it just was not very cold. So I charged it with a full can of R134a like the can said.
Afterward it was super cold but the compressor was lurching every minute or so and vibrating really bad. Not shortly afterward this, both fans start staying on for 10 minutes on the nose after the car is off.
Now the compressor will not engage at all. I bought another recharge kit with the re-usable hose/gauge. The gauge without the can hooked up was reading over 550+. So I got it to a lower pressure, but still no compressor action.
I checked all the commonly associated fuses etc. and they all seem to be good, no discoloration or anything.
I tested the power at the compressor, and got nothing. But I get some juice at the G65 sensor.
I read about some really extensive tests involving the T14 connector etc at the fan control module, but I am not too competent with a multimeter.
Any ideas?:confused:
 

·
Registered
Joined
·
52 Posts
Cody, i have checked the fuses your talking about and the fuse holders and they all seem to be fine. So your suggesting a complete fan shroud/assembly switch?? would this have a impact on my compressor not engaging? thanks man
 

·
Registered
Joined
·
8 Posts
some hints

My wife always leaves the AC switch on, ( sourthern CA).
2001 Jetta GLS 1.8T, 132k miles. The ac suddenly stopped working.
Freon pressure seemed fine when stopped and cool, ie 85~90 psi.
When the AC was engaged, the secondary radiator fan would turn on, but no cold air. Turns out the compressor clutch coil was open. Had to put in a new compressor since a clutch assembly costs the same as a compressor/w clutch. Upon disassembly, the pulley's friction surface was worn flush to the pulley body, slight scratching, so when the friction material wore down, the metal to metal friction heated up the clutch coil, and the thermal fuse opened. By passed the thermal fuse, the clutch works, but there is no friction material.
Had to vacuum the system, and reload with R134a. All is fine.
If you want to check the clutch/fan relay, you need to have a small 12 V load.The clutch coil pulls over 2A, may be it was close to 4 A. So a small 12 v lamp should be a reasonable load. When you turn on the AC switch, the lamp should light, then you know clutch coil is likely blown.
 

·
Registered
Joined
·
34 Posts
i am currently struggeling with the same problem i have checked all the electrical systems and fuses that i can there is only 2 possible things that can still be wrong...well make that 3 one being the solenoid that engages the clutch is burnt 2 being the compressor is propper f*cked or the pressure switch doesnt work...
 

·
Registered
Joined
·
9 Posts
People are saying there is no relay? I went to the dealership parts department and asked if my 2000 Golf had a relay, and he said yes. When I asked him for the location he said, my book doesn't show that info. Did I just buy a $30 phantom relay?
 
1 - 16 of 16 Posts
Top