Passenger door lock - quits working on hot days only!

A6 All/ S6 All
#1

I’ve had my '09 S6 for about 1.5 years now. Shortly after I bought it (35k miles), I noticed that the passenger door lock wasn’t working on warm days, so I replaced the entire unit with a brand new part. A few weeks ago, as the weather here was warming up, I noticed that it is doing it again.

I know that electrical resistance goes up with temperature, so I had assumed that the electric actuator had gone bad. Now I’m thinking that it must be somewhere in the wiring. I have checked and cleaned the connections at the actuator and it changed nothing.

Have any of you had a similar experience? Any suggestions on what to try next?

#2

my driver door handle stops working only in cold weather. Poor connection inside somewhere. Typicaly electrical components will either work or not if it is a true fault in the circuitry. Intermittent issues are 99% of the time connection/ground issues. Just gotta keep working back to the next subsequent connection and retesting.

#3

I haven’t had time to look into this yet, but it now seems to have stopped working altogether. When I push the button to lock the car, the horn no longer chirps and the passenger door does not lock. That door can then be opened without setting off the alarm. I’m starting to wonder if the replacement actuator has now failed?

#4

I’m starting to think that I may have a wiring issue. Last week it started working properly again. This went on for a few days, until my drive home last night. While I was driving in traffic, I heard the locks try to actuate. When I looked over at the passenger door switch, the red light that indicates the locked position was flickering. It did this several times before settling into the locked position. I tried unlocking and locking the doors several times and it worked fine. Still working fine this morning. I guess I have to tear into the door harness and see if the problem is in there. I inspected the harness in the doorjamb when I replaced the actuator last year and it looked fine. Maybe it has developed a new issue…

#5

Well, after tearing the door apart and checking all of the wiring that I could, I finally gave up and took it to the dealer. It turns out that the aftermarket actuator that I bought just over a year ago had already failed. It now has a new Audi actuator, door insulator, clips, screws, etc… to the tune of $1,150. For a door lock…

At least it’s fixed and working properly again!

#6

Oh man that sucks. Its a tough pill to swallow. Its so hard and so hit and miss when it comes to after market replacement parts. Some of the time they are good and other times it comes back to bite you on the back side.

Sucks about the cost but great to hear you got it sorted out.