AC stops cooling at idle

AC cools fine when moving down the road, but stops cooling (most of the time) when idleing like at a stoplight. 384 relay is about 4 yeas old. If I hold the idle RPM at around 1500 rpm, it will start cooling again, but usually stops cooling again if I let it drop back to normal idle. Sometimes, cycling the AC button will make it start cooling. Just started doing this after 4 years of perfect operation.

Does this sound like a 384 relay issue or something else?

The main thing I know, which is the reason most of these don't cool well, is the electric fan may have died. With motor off, turn key on with fan and AC button on--you should hear the fan.

If that is OK, you must look at the 384 relay up close; there are pictures here about where the crack occurs. Re-soldering usually fixes it. If that is it, consider keeping a spare, being in Texas is worth it, the spare that is.

Good testing advice regarding the fan. Concerning the 384 relay, if that is the problem, I replaced mine at 60,000 miles and then at 120,000 miles. My A/C would come on and off every few minutes and then just stopped coming on after a few days. It was the 384 relay. I did not tear apart my relay to repair it since I did not have a soldering iron, etc. A new, replacement VW relay is roughly $65. In the vehicle it is located above your shins/feet when sitting in the drivers seat - you have to drop the panel using a Torx driver and then its an easy unplug of the old, and plug-in of the new relay. I am in Houston, TX and I carry a spare - since Houstonians use the A/C almost year-round. The last new relay I purchased did not have the "384" painted on it in white (the relay is black); so if that is the case, you may want to somehow label the replacement relay so you are not scratching your head - the next time you have to do the job - in trying to remember which relay it is, since there are others in the panel.

384 relay can be accessed by removing the side cover seen when the door is open. The number 384 is large and easy to see. Some delicate finger work can get it out and back in without tools.

Part number 8D0-919-578-A for the 384 relay (some call it a control module).

I replaced the 384 relay about 4 years ago to fix a non-cooling problem. This issue is somewhat different because it always cools great going down the road; just stops cooling at idle. Reving up the motor in neutral causes it to start cooling agian.

Did some checking today before work and the aux fan does not come on when the AC button is depressed. My understanding is that it should run continuosly when the AC button is on and lite up. The fan will spin freely by hand.

The non-running fan could explain why:

• at a stop, it stops cooling due to lack of air flow across the condenser
• reving the motor in neutral spins the radiator fan faster and moves more air across the condenser
• traveling down the road provides sufficient air flow across the condenser to allow cooling

Now I gotta find out why the aux fan aint running. Is it controlled by the same 384 relay or something else?

most of the time, it is the basics. It's power plug is under the power steering
tank. Check for 12V, usually the fan motor has died.

Mine was the aux fan. Replacing it was fairly easy, though routing the power wires was the worst part of the job. I ended up taking a non-factory routing, and so far, so good.


Herb

Picked up a used relay and the electric fan still not working. Going to chexk the power to the fan next.

aux fan part number??

I found a part number. Dang, that thing is expensive for a fan!! Dont have VCDS, but will check for 12V at the connector. No hurry to get it fixed, since the need for AC in Texas is just about over for the year. Im also working 75 hour weeks and nights for the remainder of October, which gives me little free time or motivation to mess with it now.

I use the car for a 60 miles roundtrip work commute that is almost all rural highway, so I only have AC cooling issues at the end of the day if I happen to get caught by one of the 3 redlights I encounter. Rest of the time, it blow 40 45 degree air.

What do you think the long term negative affects would be (if any) to not replace the fan and continue using the car and AC like it currently is?

New auxiliary fan fixed my problem. Fan runs and AC cools all the time now

Exact same symptoms for me - AC compressor cuts out when idling (no cooling), starts again when moving. I too had already replaced the 384 relay, so was pretty sure that wasn't it either.

Easy diagnosis as posted elsewhere:
With the ignition and the A/C on, the AC condenser fan should run (the fan on the passenger side), even without the engine running.
If the fan does not spin, remove the Power Steering reservoir cover (molded clips - pops off). You'll find 3 wire connectors clipped on a vertical holder. The AC condenser fan connector is the one with two large wires, a brown and a red/black. The brown is chassis ground, the red with black is power to the fan. Provide power to the fan side with a 12v source to see if it operates. I hooked a battery charger up to the fan connector and it did nothing.
AC condenser fan was dead.

I bought a very inexpensive replacement fan ($40) off of eBay and it fit and worked fine. Replacement procedure is:
1. Remove engine cover, plastic air filter cover & air intake tube that goes to the grill
2. Remove top portion of timing belt cover (2 clips)
3. Remove one phillips head screw on fan's top mounting point
4. Rotate entire fan assembly 1/2" in the unscrewing direction (counter clockwise) to release it from the fan shroud.
5. Remove Power Steering reservoir cover and disconnect the fan wiring connector (the one with two large wires, a brown and a red/black)
6. Jack up car and remove belly pan.
7. Use long screwdrivers (or similar) to reach several cable clips along the edge of the radiator shroud - open the clip with one tool and pull the wire out with another. Not easy to get to these, so it takes some patience.
8. Remove the old fan assembly & wire through the top (It is very tight, but can be done by carefully rotating and shifting the fan. I cut the connector off the old wire to make removal easier.)
9. Install new fan assembly - opposite of removal.
10. Reroute wire in same location as old wire and push it under the wire clips.
11. Reinstall belly pan, TB cover, air intake tube, plastic air filter cover, engine cover, wire connector and PS cover.

Less than an hour job, start to finish.

Awesome, thanks for the write up.