Air con display flashes on start and only warm air

[reimondo]

Hi Audi fans.

I was more reading and studying this forum in the past to get my problems fixed. Now, I can't seem to find a good answer. So, here is my problem:


A few days ago it happened that after I started the engine, the display of my air conditioning started to flash for about 30 seconds. Then it stayed on as normal. At the same time I noticed that there is only warm/hot air coming out the vents.

Regardless of what temperature I set the air con to or whether or not I have it in automatic or manual, the temperature remains the same.
All controls works as per normal, so nothing unusual other than the warm air only.

I am guessing it's the thermostat?
If so, is it possible to change it as an amateur or does it require an Audi specialist?


Thanks for your help. Appreciate it.

PS:
Audi A4 B5, 1995, 2.6L with automatic air conditioning

[rhencullen1989]

Flashing display on aircon unit is usually down to a dry solder joint on the rear of the unit, remove unit from car and re-solder the joints (2 rows of joints about 16 in total)

As for warm air only, what is the temperature gauge reading, it should be crack on 90 degrees, straight up, if so it's not the thermostat, i would suggest your aircon is not working properly and will need re-gassing, does the air blow out of the vents harder when you press the aircon button, if so this shows the compressor is kicking in. Best bet is to take it to an aircon specialist.

[reimondo]

The temperature gauge is reading 90 degs. Straight up. Never seen it above that.
Yes, air blows harder if pressing the snow flake. Also, i can normally adjust the strength of the vents manually.
I'm pretty sure the compressor kicks in. Normally I realise a very slight difference in sound coming from the motor area.

This is my first car with aircon. Are the any indications that the aircon will need re-gassing soon?

Thanks for your help so far.

[rhencullen1989]

The fact it's not blowing cold would suggest it needs looking at and hopefully just a regas should get it blowing nice and cold again. Expect to pay around £40 to £60 for this service depending where you go.

[African Nomad]

Hello Reimondo,

The flashing means the AC system is in fault. When the system looses presssure to a certain level, the AC stops working. Also when you run out of coolant, the same thing happens.

I have the same problem with my SEAT Alhambra and it is going in to be repaired Thursday.

I would therefore suggest you get it seen by an AC specialist company.

African Nomad

[Senlisian]

Reimondo, does the snowflake symbol stay on or does it go off (and the compressor cut out - discernable by a change in engine revs and a 'click' from the front of the engine if the bonnet is up and it's not a clanky diesel drowning out the sound)?
If the gas charge is too low (leaked out) the pressure sensor will cause the a/c compressor clutch to disengage in order to protect it from damage.
If the snowflake stays on that means there is gas in the circuit & your problem lies elsewhere (like mine...).
A caveat being that the pressure sensor might be faulty but this will show up on a VAG-COM diagnosis.
In any case, you'd best get an a/c specialist to perform a diagnosis - including hi/low pressure testing and UV dye leak testing.

Good luck.

[akalebic]

I was in repair shop recently with same problem on my B5 Passat. The problem was faulty A/C radiator electrical fan next to the visco fan. The flashing means there is fault stored in A/C since the last trip. I initiated self diagnostic and the result was hi pressure sensor trip. That means that the compressor develops too high pressure due to missing cooling down the refrigerant. My advice is to check radiator fan fuse or radiator motor.