Where is the A/C clutch fuse ?

I’m following the instructions from Audi’s Tech Bulletin 87.05-01 «Musty Odor from Heating and Ventilation System». One of the first steps is: «Remove A/C clutch fuse from instument panel fuse box, if applicable» The only fuses that come close are:

fuse #1 Air Conditioning
fuse #6 AirConditioning, pressure sensor

The procedure requires that you have the climate control on in Econ mode with the fan on high. Fuse #1 shuts everything down so that leaves fuse #6. Is #6 the «A/C clutch fuse» or is it «Not applicable» on my car. Its a 2002 A4 3.0 6 speed.

I could not find a link to the Service Bulletin and I dont know how to post a pdf file so I’ve summarized the procedure below.

You can also search the forum for «musty ac» and get more info
Unpleasant «musty» odor from Heating and Ventilation system.
Odor mainly occurs after vehicle has been sitting (unused) at least 5 hours and within 20 to 60 seconds after vehicle is first started.
This odor may be caused by residual condensate in and around evaporator mixing with airborne pollutants. This forms the growth of bacteria and or fungi (mold).

First you need to dry the evaporator core.
— Remove air intake filter
— Place a catch basin below evaporator housing drain valve.
— Open all A/C outlet ducts.
— Cover all A/C outlet ducts with paper towels
-Set HVAC Control as follows:
— Econ mode ON.
— Temperature to Hi.
— Blower to hi.
— Air distribution to A/C ducts.
— Driver side window open. All other windows and sunroof closed.
— Start and run engine for approx. 20 minutes.

Next apply treatment
Airsept Application
— Install Airsept onto applicator tool.
— Connect applicator tool to shop air.
— Position applicator tool nozzle in air intake just above blower motor cage.
(DO NOT contact blower motor cage)
— Apply short bursts (approx. 3-5 second) of Airsept treatment.
— Continue treatment until bottle is empty.
— Continue running engine for 20 min. to dry treatment.

I don’t have compressed air much less the applicator tool so I substituted the Airsept treatment with «Clean n’ Coat» by ATP
For reference the Airsept website is www.airsept.com

For good measure, I followed up with a few sprays of Lysol through the air intake. So far the smell is completely gone.

If you Google «Musty Odor from Heating and Ventilation System» you will find some bad links to the Audi TSB and some good ones to the VW version.

  • Clean n Coat