'04 - A/C weak, NOT empty. No HVAC codes.
07-29-2015, 10:43 AM
#1
AudiWorld Super User
Thread Starter
'04 - A/C weak, NOT empty. No HVAC codes.
Indy shop I deal with said the a/c fan did not kick on, but they shut off the a/c and turned it back on and they/it came on. I gave them the car to do a full a/c service. it is full to factory specs, but its not very cold at all.
Anyone run into this before? Please chime in.
TIA,
Dan
Anyone run into this before? Please chime in.
TIA,
Dan
07-29-2015, 02:20 PM
#2
AudiWorld Super User
If the gauges read proper pressure, the shop should evacuate and refill with the prescribed amount of refrigerant in case someone did the benzine or propane scam fill.
Now, if you know that didn't happen, then the gauges will tell if the compressor is working or not and if there is any line blockage.. If working properly, the suction line should be very cold near the condensor. If so, all that is left is the blower fan, which is a common item to fail. Otherwise a flap is stuck (should see a code but you never know with these wacky German cars) or duct (s) from the evaporator could be disconnected somewhere.
Now, if you know that didn't happen, then the gauges will tell if the compressor is working or not and if there is any line blockage.. If working properly, the suction line should be very cold near the condensor. If so, all that is left is the blower fan, which is a common item to fail. Otherwise a flap is stuck (should see a code but you never know with these wacky German cars) or duct (s) from the evaporator could be disconnected somewhere.
07-29-2015, 08:51 PM
#4
AudiWorld Super User
Agreed with all Mister Bally said for starters, especially relative to being sure they filled it by weight starting from empty, rather than just trying to use pressure gauges.
Other possibles are the various sensors, especially either the outside air temp one, or the inside ambient air. I think there are two of the latter. They work in tandem with some obscure algorithms, and if bad may not show codes. Outside one ties to displayed outside temp of course as one easy check.
Yet another is that the heating control block is still letting hot water pass through it when it shouldn't. Doesn't throw codes. You could try feeling heater hoses or IR reading them. If both are hot in summer conditions with interior temp set low, that would be a clue to look further.
Other possibles are the various sensors, especially either the outside air temp one, or the inside ambient air. I think there are two of the latter. They work in tandem with some obscure algorithms, and if bad may not show codes. Outside one ties to displayed outside temp of course as one easy check.
Yet another is that the heating control block is still letting hot water pass through it when it shouldn't. Doesn't throw codes. You could try feeling heater hoses or IR reading them. If both are hot in summer conditions with interior temp set low, that would be a clue to look further.
07-31-2015, 11:24 AM
#5
AudiWorld Super User
Thread Starter
Thanks!!
I will check those hot water piping and move onto checking sensors.
I do have the Bentley manual for the D3. Phew, but sure hope it can help me verify the sensors.
I do have the Bentley manual for the D3. Phew, but sure hope it can help me verify the sensors.
08-06-2015, 10:18 PM
#7
AudiWorld Super User
Updating this thread from a few weeks ago for general reference. FWIW, I just came across the TSB again that deals with the ambient air sensor and fits the thread issue in general: http://uberlame.com/a6_tsb/HVAC/Clim...fficiently.pdf
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