2005 Cayenne V6 A/C Fan Relay Replacement

[RNajarian]

I thought I would share with the group my experience with the replacement of the A/C fan relay in my 2005 Cayenne V6.

I am the original owner of this truck. It has been pampered since I took delivery of it in February 2005. It is very low mileage with only 51,000 miles on the odometer. The air-conditioning has been finicky to say the least over the years. While it was under warranty I had to take it to the dealer for repair when it was blowing hot air on the coldest setting.

Prior to attending my nephew’s USMC graduation at MCRD in San Diego I decided to service the A/C. With the temp sent LO and the fan on full, I wasn’t really getting any cold temperatures, 75 vent temp on an 84 degree day. I checked the refrigerant level and it was pegged to the upper limits of the safe level on the gauge. I recovered 16 ounces of the refrigerant and replaced it with a different brand of refrigerant. Two or three years ago I had topped off system off with a (cheap) generic 134a refrigerant. I had the idea of maybe actually spending a little extra money and getting some quality refrigerant might make a difference, it did. I was able to get better than 45 degrees cooler than ambient when I put in the quality 134a.

So the next day off to Marine Corps Recuiting Depot we went. I left my vent thermometer in the vent the whole way down to monitor the system’s performance. It registered vent temps as low as 41 degrees on a 82 degree day.

The problem was that despite setting the fan level at MAX I was getting only a mere draft from the vent. Occasionally the fan would speed up, but for the most part the fan performance was pretty anemic.

I had experienced this issue a few months ago so I went ahead and bought the appropriate A/C fan relay from our host, however I was chicken to replace it.

However, after this trip, I decided it was time to take the plunge. Using a tech Article here on Pelican I was able to replace the bad relay in about 45 minutes. The only thing I would add is to disconnect the two wire pigtails from the relay PRIOR to removing the relay from the vehicle. Inadvertently I touched the metal cooling fins of the old relay to an exposed metal portion of the truck and closed the fan circuit. All of a sudden with the key out of the ignition the A/C fan fired up. Removing the metal part of the relay from the chassis stopped the fan.

After installing the relay and replacing all the panels I fired up the A/C to test the fan. The fan performed BETTER than it had in a long time. A lot of air volume came out of the vent, much more than prior to the relay swap.

That’s it. The replacement was extremely easy, I wish I had done it earlier.

Oh and if anyone is interested . . . The graduation was GREAT! Proud of my Marine (marksman) Nephew