A.C. Malfunction when on Auto

[gregozedobe]

So we can't help but think there is a vent that is broken or jammed somewhere.

Bugger - the last thing you need is a non-functioning A/C when you are doing a trip in hot weather (and we've all had plenty of that lately). It does sound like there is some kind problem with the vent controls.

pre-2008 (?) T5s with manual A/C are susceptible to bending the actuating wires from the rotary control that selects which outlet should receive air. I don't know whether this would result in no air being output at all.

VW "fixed" the problem by mechanically preventing the knob from rotating 360 degrees. The poor man's fix (which I am using), is to only ever rotate this knob anti-clockwise

[Seano]

If it is any help......only the manual vent controls in the T4 were actuated with wire cable.

All of the switched controls (like fresh/recirc) use a vacuum switch with the vacuum generated by the engine. And the pipework is simple rubber tubing. Only has to have one hole and it is cactus. Oh and the flaps are weighted slightly too hence the thump when they hit home.

All of this gives me reason to think that the T5 setup may not be that different.

[Silver Caravelle]

I agree with Seano,

In my previous T4 Caravelle, I had a simliar issue. It is likely to be a vaccum leak somewhere in the air vent vacuum circuit. Mine turned out to be the vacuum actuator that operates the recirculation flap under the glove box had a split in the actuator 'bladder'. A trip to Pick-a-part, got me a replacement one out of all things, a 86 PUG 505 GTI; it was identical to a 2000 Caravelle! All for $5 plus a another spare.

Odds on the T5 is not going to be too much different. The challenge may be locating where the vaccum leak is.

Another test is to see if vent air flow changes when accelerating with A/c switched on. The airflow will return when deaccelerating and reduce when accelerating indicating a vaccum leak.

Regards,

Scott

[gregozedobe]

Another test is to see if vent air flow changes when accelerating with A/c switched on. The airflow will return when deaccelerating and reduce when accelerating indicating a vaccum leak.

That only applies to petrol engines. AFAIK most T5s in Oz have diesel engines. I wonder if Vagcom/VCDS will show an error code to help locate a leak ?

[Silver Caravelle]

That only applies to petrol engines. AFAIK most T5s in Oz have diesel engines. I wonder if Vagcom/VCDS will show an error code to help locate a leak ?

Yes, very good point re diesel engines. Thanks.

My money is on one of the vaccum actuators have developed a bladder split.

Cheers, Scott

[Silver Caravelle]

Hi IVO,

Dis you get this sorted in the end?

Cheers,

Scott

[Ivo]

The saga continues! The motor has been rebuilt and runs perfectly but the air is still trapped in the dash The rear AC is working perfectly and if I set the front temp on about 19 it blows just a little air. If I set it any colder it trips out the entire system after about 30minutes. Then I have to turn it off and let it rest for 10 minute then start the AC again. All the actuators in the dash test as ok on both VAGCOM and the Bosch System...so the motor is working but a flap is not.

We pulled the pollen filter out and you can feel the air speed change with higher and lower settings. Its blocked somewhere after the "small radiator" in there. That means most the dash has to come out to get at them Its just been a matter of time to schedule it for a few days to get it all apart. Its booked in next Wednesday for a few days.

[Silver Caravelle]

The saga continues! The motor has been rebuilt and runs perfectly but the air is still trapped in the dash The rear AC is working perfectly and if I set the front temp on about 19 it blows just a little air. If I set it any colder it trips out the entire system after about 30minutes. Then I have to turn it off and let it rest for 10 minute then start the AC again. All the actuators in the dash test as ok on both VAGCOM and the Bosch System...so the motor is working but a flap is not.

We pulled the pollen filter out and you can feel the air speed change with higher and lower settings. Its blocked somewhere after the "small radiator" in there. That means most the dash has to come out to get at them Its just been a matter of time to schedule it for a few days to get it all apart. Its booked in next Wednesday for a few days.

IVO,

This is worth a try before you go to the pain of pulling the whole dash apart.

If you can some how access the vacuum actuator for the recirculation flap (somewhere under the left hand side of the dash), this may be where the air leak/perforation is. At least this was the case on my previous T4. The T5 might be laid out slightly different. The symptoms you describe relating to the temp settings may mean the recirculation flap is not closing when A/c is set below 19 to 20 c......because of an air leak relating to the recirculation flap actuator ......which gives the impression that it is a temp related….. but really means an vacuum leak because the flap closes below this temp range.

Clear as mud!

Cheers,

Scott

[Ivo]

Its not vacuum actuated, they are electrically operated.

[Ivo]

Dash is out and still no luck We have stuck a camera down the ducts to check for blockages....nothing! Still got some more investigating to do though.