Porsche Boxster Ignition Switch Replacement

Broken Ignition Switch

The original-type Ignition Switch on my Boxster has broken twice now. The switch is located about 6-8" behind the key, at the end of a metal assembly. It's accessed from under the dash, not from the key side. My first switch was replaced under warranty, which would have been around '99 or so. By that time, the switch was already on it's fourth (4th) and final iteration. My '99 replacement switch had the same part number as my new (Nov) 2005 version. The second switch broke in late 2005, at about 35,000 miles.

Symptoms and Electrical Issues

Symptoms of a broken switch include: breaking plastic sound while moving the key (one time), difficulty inserting or removing the key, unusual 'key feel' while turning the key, and/or the car 'thinking' the key is still inserted even when it's removed. In my case, the 'key feel' was different and my dash lights stayed on. Depending (reports vary), the car thinks the key is still inserted, so the lights, dash, fans, etc. still work. With the electrical functioning, even sporadically, the battery drains. It's important to pop the front hood before the battery goes dead, or you'll have to figure out the trick to getting it open. The door sill hood release won't work if the battery is dead!

I'm lazy and I have a charger, so I let the battery drain. You probably aren't lazy, so open the hood and pull off the negative battery lead. You'll have to do that anyway while replacing the switch, so you might as well do it now. Oh, yea... make sure you have your radio code before pulling the battery!

Audi part # 4A0 905 849 B

This part is apparently used in the 986, 996, possibly other Porsches, and various Audi and VW cars. Eventually, Porsche gave up on this easily broken part, and switched to an entirely new lock assembly. The part is no longer available from Porsche, but can be purchased through an Audi or VW dealer. Some Porsche dealers encourage the customer to replace the whole assembly, which is far more expensive in both parts and labor. It's also probably not an owner-doable job. My Porsche dealer knew the part, and cross-referenced it for me to Audi part # 4A0 905 849 B. Because my Porsche dealer is out-of-town, I called my local VW dealer and ordered it for about $35.

Removing the Switch

It's easy to replace. Well, it's relatively easy. Keep in mind that I regularly swap new axles and transmissions into my Jeeps, fabricate and weld new parts for them, and can generally cause all kinds of mechanical mayhem around the house.

Ignition Switch, Audi part # 4A0 905 849 B Remove the front seat Loosen and remove the air duct above the driver's knees.

Anyway, it's pretty easy. The hardest part is the contortion effort of getting under the dash. Save yourself a ton of effort, and remove the front seat. It takes a special tool (a kind of reverse Torx socket), but I cheated and used a 6-point 10mm socket. Piece of cake. I didn't even remove the electrical connection from the seat (didn't have the patience to figure it out), and just laid the seat outside the door. Note the picture: Yes, I regularly park with my top down under a eucalyptus tree. And, no, I don't keep my car detailed. I'm a naughty Porsche owner. Not the car... me... I'm naughty. The Porsche is good. Yea... never mind. :P

To access the switch, remove the behind-dash air duct. It's not screwed in or mechanically attached in any way. It's just stays in place by itself. It comes out a lot easier than it goes back in, however. During reassembly, just be patient and it will go back in. I had the easiest time by plugging in the clutch side of the duct first.

Locate the Ignition Switch harness. Remove the Ignition Switch harness from the broken switch.

Disconnect the negative lead to the battery. With the seat and air duct removed, locate the switch and unplug the harness. The switch is held in place with two little screws. They're covered in chalky red paint and are easily located. With a small flat-head screwdriver, loosen the two screws. The switch comes out easily. If it seems stuck, try loosening the screws some more. It took a few turns each for me.

Small Screwdriver

I modified my smallest screwdriver to do the job. The tip was already ruined from years of abuse, so it needed to be 'repaired' anyway. With a steel file, I narrowed the blade and sharpened the tip. You can also see in the picture that I cut off the handle, which created an overall smaller driver. It was barely short enough. A shorter blade would have been nice, but that would have taken an extra three minutes to cut the steel in half and re-file the tip. In the end, it worked fine as-is.

Locate and loosen the red retaining screws. Remove the broken switch. Buy or manufacture a small flat-head screwdriver.


Pop in the new switch, and put everything back together. Piece of cake!

Here's more information I found on the web while researching the fix:



Ignition Switch, Audi part # 4A0 905 849 B

Update from Jerry Mullins (May 18, 2008)

Subject: 1997 Porsche Ignition Switch

I read your article regarding the replacement of the ignition switch on your 1997 Porsche. I likewise am in need of replacing my switch. I seem to remember it was replaced by the dealer in the early 2000's. It was done on a recall, I seem the recall they were "doing me a favor" when the engine wouldn't shut off! Well I have the exact problem's you cite in your article.

I am in the process of ordering the switch, but when I typed in Audi part # 4A0 905 849 B on the web up came two part numbers as follows:

Ignition Switch
NOTE: Can also update to late style lock assembly with late type switch # 996-347-017-07-M100, 996 Carrera 2/4 (1999-03), 996 Turbo (2001-03), Boxster/Boxster S (1997-03)
Brand: Genuine Porsche

Ignition Switch, Electrical Portion Only
(NOTE: Only for cars with an original lock assembly), NOTE: Can also update to late style lock assembly with late type switch # 996-347-017-07-M100, 996 Carrera 2/4 (1999-03), 996 Turbo (2001-03), Boxster/Boxster S (1997-03)
Brand: Meyle [Photo]

The "NOTE: Only for cars with an original lock assembly" concerns me. DO I need to replace the key housing as well as the electrical switch? I was (like you) have a difficult time inserting my key into the lock. Which part do I need?

Thank you

Jerry Mullins

Update from George Giggey (July 28, 2008)

Subject: Boxster Ignition switch replacement

I had the same symptoms as in your case except that my switch lasted for over 50K miles. I checked my local Porsche dealer to see if my 1999 Boxster was on any recall for the switch. It was not and they estimated the replacement cost to be $500- $600!

I went home to my computer and ordered the Meyle switch for $8.78 from Autohausaz.com. Actually, they were so inexpensive that I ordered two and had them shipped UPS two day air for a total of $40.88.

I followed your fine instructions using the photos for guidance. I did not take out the driver's seat but retracted and lowered it as much as possible. I used a small Rubbermaid step-stool that was the same height as the door sill outside the door to support my rump as I wiggled my way under the dash. I used Q-Tips moistened with lacquer thinner to get the red thread sealant out of the screw holes and then used a small (#4-5) driver bit with an extension and a small ratchet wrench to loosen the screws. You have to withdraw the two small screws about 4-5 turns (until the screw heads are flush to slightly overflush with the housing) to get the switch out. The new switch went right in and the connector fit onto the new switch with no problem.

It would be nice to have a willing assistant to pass you the wetted Q-Tips and to recover dropped screw bits, etc. so you don't have to wiggle in and out too many times. I have a small crease in my forehead from the clutch pedal but, all in all, it was an easy job.

In reading the PCA Technotes, it seems that the $500-$600 Porsche updated fix is to also replace the lock and steering wheel lock. That assembly is available at Auto Parts Warehouse for about $145, but you have to take out the instrument panel to make that replacement. So far, I am happy with the switch swap and I still have another spare if the replacement only lasts another 50k miles! Thanks for the guidance in your note and I hope that my experience will clarify some of the dirty details.

George Giggey

Berkeley | Boxster