blankhopp

Hi!

So I have searched the forums and luckily I have read about this problem before I now got it myself(Thanks guys!).

Situation: When I was out driving there was a noise still coming from the car after parking. It came from the left side just in front of the left wheel. I got home quickly to get tools and disconnect the battery. (It took 20 minutes to get home). It did have a yellow light on earlier (suspension) this same day that dissapaired after I stopped the car a few hours earlier. Just when I started the car on my way home there was a short 2-3 second loud noise from the engine-bay(possibly compressor or something related?). There is no change in rideheight and the idle-sound before disconnecting the battery was just the same as when I first heard it(no loud noise).

Now the car is in the driveway and I have been looking for a 40A/12V relay to change it myself tomorrow. Is there anything I should do except for changing the relay and what relay should I look for?

I have found good guides for both changing the compressor(if needed) and for changing the relay. I hope the relay is gonna be enough doh. It's a W12.

Mister Bally

Most of those other threads have all of your answers. You have to decide if your compressor is still good, needs replacement or a possible internal repair. Standard automotive (electrical, mechanical and pneumatic) troubleshooting techniques are required.

Having a service manual and VCDS is assumed. Although since there are so many threads that discuss the ECAS (Electronically Controlled Air Suspension), you might be able to get by without a manual for this. That said, I recommend you have the manual.

Also, you have read this I presume: https://www.audiworld.com/forums/a8-...-read-2877219/

blankhopp

Thanks Bally!

Yes, I have read the sticker and gone through lots of posts. Actually I have read the posts before and that's why I got home fairly quick to cut the power and save the compressor(If relay). I guess my main question is probably if the new relay could be something like this one? Relä - Enkel 12V 40A - Laitis AB

MP4.2+6.0

Current part # should be 4H0 951 253A. Search Google images and you can see lots of pictures of it. The one I got has the "645" number stenciled on it with some white laser type printing. What I got a few months ago for my 2006 W12. In US they are very cheap, like <$20 U.S. from a discounted dealer. Here is a thread w/ pics BTW: https://www.audiworld.com/forums/a8-...-fuse-2835590/

blankhopp

Thank you! I have just ordered one relay and will get it in two days. It was priced at $20+mail. A bargain! Now I just need to wait for it and install to see if it will fix the issue at hand.

blankhopp

Only problem now is that I managed to close the trunk with the battery disconnected. So I guess I have no alternatives?

I am gonna have to cut a hole to fit my new skibag! I don't like this! lol

dvs_dave

You can open it manually with the key....

blankhopp

Ok. Please pass me the permanent marker so I can write stupid in my forehead! I just got a bit ahead of myself there. Didn't work at first but after adding lots of 5-56(oil), luckily I got the trunk open and the battery connected. Someone should start a threat with images on how to open the trunk of an A8 with a key. Or, atleast a "audiworld for dummies"-section? LOL

blankhopp

To follow this up: Fixed it, and now working as normal.
1. Order new relay (+fuse if necessary).
2. Remove interior trim, left and right side of steeringwheel.
3. Remove 6 torx-screws.
4. Flip the cover down.
5. Change relay.
6. Put it together.

As a tool to remove the interior-trim I used a plastic butter-knife. Perfect for the job! Don't have the partnumber for that one doh.

This video really helped with location of screws and relay.

Doc_A8

Again, this site saves my bacon.

My relay froze up today, noticed it when I parked at the house. I immediately disconnected the battery and looked up this thread to get the right relay and find the location.

Have not cycled the pump yet, I'm hoping I caught it early enough that all is still well....