A few months after replacing both the evaporator and heater core in my '96 A4, the a/c no longer blew cold air. At first this was an intermittent problem, then it became constant. Of course this was just as our first heat wave hit. I decided to pull the codes from the head unit as a first step. I did this twice a few weeks apart. The first time I pulled 08.7 Temperature Regulator Flap, sporadic block. Then when the problem became constant the code switched to 08.5 Temperature Regulator Flap, static block, Made sense. I confirmed the code with a VAG scanner. Had to use a Maxscan because my shareware VAG-com and cheap e-bay cable would not read the HVAC module.
I ordered a replacement temperature regulator flap motor from genuinevwaudiparts.com P/N 8D1820511A. The actual motor is held in place with three small screws and is easy to remove, however, getting to the motor is a PITA.
I followed Bentley pretty much word of word. The motor is situated behind the center console behind the footwell vents.
To give perspective of what needs to be removed to get at the flap motors:
1. Disconnect battery- always a good idea when messing with connectors and anything near the airbags.
2. Remove radio (make sure you have the radio code if your system is stock)
3. Remove the faceplate surrounding the radio and climate control head unit. This is held on with two screws that are visible once radio is removed. Radio removal tools can be made from Pendaflex folder hangars I did use a hacksaw to cut the notches to a more accurate size.
4. Disconnect climate control head unit
5. Unplug connectors for flashers, fog lights and seat heaters, unplug cigarette lighter connector.
6. remove control panel.
7. Remove rear center console, Remove parking brake trim. Move both front seats all the way back and pry off the small cover on each side. Remove the bolts. Remove rear ashtray. Remove nut. This will probably loosen the rear portion of the console enough to enable the removal of the front portion.
8. Remove front center console. Pry out small covers on sides and remove nuts. You will need to remove the shift ****. If you have a manual- it just unscrews. If you have a tiptronic- not sure.
9. Remove glovebox
10. Remove passenger side kick panel. Remove side cover of dash to expose 2 screws. Remove screws from side attached to center console frame.
11. Remove driver side kickpanel. Remove dash side cover over fuse panel. Remove the screw (think there is only one on this side. Pry off the two plates along the front of the panel and remove the screws
12. Remove airbag control unit. Its the square box on the floor with the orange connector. Its held in place by 3 screws. Make sure your battery is disconnected. I ended up realizing I did not need to remove this once I decided the footwell ducts were not coming completely out.
13. Remove the ducts that send air to the rear seat compartment. They just slide off.
At this point Bentley CD says to remove the footwell vents. Well, to do this one needs to remove the center console support rails which, as far as I could tell, meant removing the entire dash. What I did was to leave the support rails alone and dash intact and not remove the footwell vents, but I did remove the screws holding the footwell vents in place in order to loosen them up. I was able to move the footwell vents enough to get at the flap motor. The motor is held in place by three screws which are really very small bolts. Because I did not completely remove the footwell ducts, I had a tight space to work in. A small ignition wrench worked perfectly to remove the screws.
The temperature regulator flap motor is the black one. There is a FAQ that says its natural. The blue motor is for the central air flow flap. If its your defroster flap motor, that would be the red motor that is mounted vertically between the firewall and climate control head unit. That motor can be seen from the driver side looking behind the console.
Before proceeding I reconnected the airbag control module since it really was not in the way and reconnected the a/c head unit. I turned it on just to confirm my diagnosis. Sure enough, the arm on the motor did not move as I changed the temperature. I manually moved the arm and the hot air changed to cold. Just a check to confirm the malfunction of the flap motor as being the cause of the problem while I had everything all opened up. I swapped in the new motor and everything worked on its own. I then re-disconnected the a/c head unit.
Making it simple, just put everything back together in the reverse order in which you took it apart. Everything went back together much faster than it came apart. Then again I had never taken apart the console before so had a learning curve. Everything went back fine, although I ended up with 4 extra screws. That's what I get for putting things back together from memory. I suggest labeling some of the connectors especially if you have an aftermarket radio. Most connectors in there are pretty obvious but some aren't.
When you are done, check for HVAC codes and clear them with a VAG-com or VAG scanner.
My old A4 now had icy cold air conditioning like it never had before, although the new found cold air exposed another problem. water leaking into the passenger side footwell from the foam ring at the evaporator drain.
The reason I mention this here is that in the process of investigating the source of the leakage, I might have discovered a short cut to getting to the temperature flap motor.
I removed the glove box and passenger side kick panel in order to pull the carpet up to get at the drain funnel. I didn't want to take the entire console off again so I only removed the kick panel without removing the center console. It took a bit of prying around but the kick panel came loose. Once off, I noticed the flap motor in plain view. I think with some effort, one could get the screws holding the motor out with a tiny wrench. I did not try this, it was merely an observation I made.
If you choose this method, putting the kick panel back on was a bit harder as it has to get tucked behind the edge of the center console. The edge on my console had a small crack in it already, so I had some "give" and was able to get things back together. This area is hidden by the glovebox anyway.