need some help, have a 2003 golf gti that came for another shop. The ac will not work at times, the high side pressure reach 400 plus at times also. The other shop replace ac condensor due to leak, then installed compressor, dryer and expansion valve. none of this fixed the ac problem. we installed a new fan control module and the car was fixed for 2 days over the past weekend. now back with same concern, tried high side pressure switch, but no change. Only acts up when driving. Does not have climate control system and ac compressor is turning off.
Not sure, what are you thinking? This concern has been there before any parts were installed. I guess what has been happening before we got the car is high side pressure went so high that it blew out condensor? That what I was told. Must have been weak or had a hole in it already. The compressor blow off valve should go first I would think. Any ideas? Oh I almost forgot, the shop who install condensor, dryer, expansion valve and compressor cant tell me if the put oil or how much in system. Is not slugging and sounds normal when compressor is engage and work fine for 2 days after cooing fan module.
-- Edited by joecarparts on Wednesday 18th of July 2012 05:02:11 AM
1. All tests are performed with the ignition key and A/C switched on and the connectors connected to fan module. The fan control module is located under the radiator and has 2 connectors; a 14 pin (T14) and a 4 pin (T4).
2. Check for 12 volts to pin T4a/1 (Red/Black) and T4a/3 (Red) via fuses S164 and S180 respectively, in fuse box on top of battery, at all times.
3. Verify approximately 70% duty cycle from the A/C pressure sensor at pin T14/2 (White) with the ignition on but the compressor not running (duty cycle will decrease as the high side pressure increases). A duty cycle above 80 or below 10 will command the compressor off and would indicate a faulty pressure sensor if the compressor is not running and the refrigerant levels are normal.
4. Verify 12 volts to pin T14/4 (Red/Gray) via fuse 16, at all times.
5. Verify good ground to pin T14/6 (Brown/Black).
6. When the A/C is switched on and the blower motor is running at any speed, verify that 12 volts from the A/C switch in the instrument panel is available to pin T14/8 (Blue/Red). NOTE: The cooling fans should run at low speed whenever the A/C is switched on.
7. Verify 12 volts to pin T14/9 (Black/Blue) from fuse #5, when the ignition is in the "on" position.
8. Verify the presence of an 11 volt reference (actual voltage reading will oscillate between 7, 9 and 11 volts) at pin T14/13 (Purple/Yellow). The instrument cluster will ground this reference to request a compressor shutdown for an overheat condition. The cooling fans will also be running on high speed.
9. Disconnect the 14 pin connector. Using a fused 12 volt jumper, apply power to pin T14/10 (Green/Black). The compressor clutch should engage. If the compressor does not engage, check for wiring harness open circuit or loss of ground at the compressor. Reconnect the 14 pin connector.
10. Disconnect the 14 pin connector and verify continuity between pin T14/14 (Green/Blue) and T14/5 (Blue/Red). This checks the Ambient Temperature Switch (ATS) (normal open circuit below 32 degrees F, continuity above 32 degrees F).
11. Verify the presence of an 11 volt reference voltage at pin T14/3 (Green). The Powertrain Control Module (PCM) will ground this reference to request a compressor shutdown for a Wide Open Throttle (WOT) condition or lack of throttle basic setting. 11 volts is the normal expected reading at this pin.
12. If all tests pass, the Fan Control Module (FCN) is faulty and must be replaced.
-- Edited by chopstick on Wednesday 18th of July 2012 08:41:46 AM
i'm thinking some new aftermarket parts are worse than damaged oem parts ...
see if you can get the old condenser and compressor so you can look at them ..you need to know how much oil was in that old compressor
did you instal a new vw fan module from dealer ,used or aftermarket ?
how about the thx ..is it an oem part ?
if the other shop doesn't know if they put oil in ,then i would be checking their work ......sounds like they just put parts on and didn't do any diagnosis after the damaged condenser was replaced
do the fans turn by hand?..is there something blocking the front grille area or missing baffels under car ?
it only acts up when driving ?.........has anyone checked the water pump impeller ..make sure it's still there ..remove thermostat and you can see and touch it ...maybe the engine is getting hot and the ecm is turning of compressor
Customer's complaint: AC working fine then suddenly cut out.
Initial inspection: Clutch not engaging. A/C system is charged. A/C switch illuminating when on. No comms with A/C module. Test light showed all A/C related fuses are not blown.
A touch of research seemed appropriate before digging out the module to test powers and grounds: No TSBs. IATN Tech Help history held the silver bullet. One of the three fuses on top of the battery had burnt a terminal and melted it's holder. A little cleaning of the contacts brought the A/C back on, and the VW dealer had the fuse holder (1C0-937-617) on the shelf for the more permanent repair.
So, this could be a tip to save some time on a VW AC repair, or it could be a tip to pull suspect fuses for inspection. You decide.
