Jetta A/C = 10 minute warm up?

jetta
volkswagen

#1

First of all, I live in Florida. In April, took my wife’s 2007 Volkswagen Jetta 2.5 to my local import repair shop to have the a/c looked at. I explained that it took about 5-10 minutes to cool, depending on driving conditions. They looked at it, checked the pressure and said it looks fine. No problems. It also wasn’t a very hot day when they looked at it. So now I need some help diagnosing this problem so maybe I can fix it myself. To better diagnose, I have the following facts:

  1. From a cold start, when the a/c is turned on and set to highest fan speed and coolest setting, both engine cooling fans do not spin.
  2. While driving- the higher the rpm’s, the faster the a/c gets cool.
  3. Cools faster at highway travel.
  4. After returning from a drive and parked at an idle, the engine is hot, both engine cooling fans are seen and heard running while a/c is still on.
  5. While idling in the driveway after a drive, when I decrease the a/c interior fan speed to 1 or 2, the engine cooling fans slow down.
  6. While idling in the driveway, when I turn the a/c off, the engine cooling fans slow further.
  7. A/C is ice cold when working, maybe 45 degrees.
  8. High and low pressure are correct.
  9. Engine temp is within normal limits.

Does anyone know what part I need to repair or replace? Thank you all for your insight.


#2

I think you’re going to need more tools and equipment than you have at home. A set of automotive A/C gauges, a capable scan tool, maybe a DVOM and wiring diagrams.

I would want to know if the compressor is running immediately when you first start the car. I would want to know the operating pressures of the system when it is functioning properly. I would want to know if there are any fault codes stored in memory for the HVAC system, and I would want to look at all the data of the system --both cold and hot–to see if the car is not allowing A/C operation or if it is requesting A/C and it is not responding for some reason.


#3

I can’t be specific at all but you state several times the pressures are correct.
What are the high and low side pressures and at what RPM?

While it likely was not done, my opinion is that info such as A/C pressures, compression test numbers, oil pressure numbers, etc, etc should always be notated on the repair orders.


#4

“A/C is ice cold when working, maybe 45 degrees.”

If you mean any time A/C is on, then I see no problem.


#5

Thank you for taking a moment to respond asemaster and ok4450. The high and low pressures were done by the shop and not noted. I will contact them. And the compressor clutch does not engage until it’s been running for a bit. Even if the car is still hot from driving home. If it sits for more than 10 minutes, the clutch will not engage for a bit. And these are warm outside air temps of 85 to 95 degrees.


#6

If the clutch for the A/C is what is taking 10 minutes to engage, then the A/C control module is either faulty or is receiving a signal telling it not to engage. Once it engages, all is fine, right? The module and inputs need to be evaluated.


#7

It could be a simple as a weak relay. VW crammes a lot of relays in the car, but they all have numbers printed on them.