If you’re an owner of a BMW E39 5-series between the years or 1997-2003 then odds are you may experience or have experienced what is known as seat twisting when trying to recline or raise the back of your seat. There’s probably many other BMW’s that experience this issue but the following fix is done on a ’99 BMW 540i some some steps may differ if you have another model or year BMW.
This rather annoying occurrence means you either leave your seat reclined in one position for the rest of its life or fix it! Which isn’t that difficult and aside from a few supplies it’s doesn’t cost you anything but time.
The reason the twisting occurs is that the back of the seat’s left and ride side are independently controlled through cable operated electric motors and almost always one side cable fails not both hence the awkward twisting of the seat.
What you see in the photo above is the culprit of all our troubles. It’s the cable that operates the recline/raise function and over time the plastic shielding around it ages and expands which causes the cable to retract out of the electric motor that spins it. Thankfully, the fix can be done by any novice DIY mechanic.
Start be removing the twisting seat from the car. There are four bolts holding it to the floor and an electrical harness that you have to disconnect before it’s free.
Once it’s out of the car, flip it upside down and this is what you’ll be looking at.
Pro-tip: If you’re working on the passenger side seat, it has an additional cable attached to it that you’ll need to pop off and before the seat can come out. After you removed all the bolt, tilt the seat up which will give you easy access to it.
Look at the front of the seat base, we’ll need to get access to the electric motors but there’s no real way to get at them without lifting the metal base of the seat up and away.
Using a torx bit remove both bolts that hold the metal base to the seat.
There are two tension springs that are a bit of a pain to get at but using vice grips and a lot of determination they’ll eventually unhook.
Remove the plastic trim that runs around the base of the seat. If you’re lucky like me you’ll find coffee stains and many stray strands of hair.
At this point, the base of the seat should swing up with relative ease. Place a block or similar object to hold it up. You’ll notice that I have already unplugged the connectors from the electric motors. If you haven’t done so yet now is a good time.
We got great access to the motors now but the battle isn’t over yet.
I keep on blowing the fuse for the driver’s seat. I did this repair and the seat works perfect but I blow the fuse after a few uses.
Thanks for this step by step. It would have been incredibly beneficial if you included “how to” remove the cable on the passenger seat. It was definitely not intuitive. I had to go to other sites.
Thanks again and perhaps include that and the tools necessary (i.e., T-27, T-50, 8mm, etc.)
Hi can you tell me what the tension springs do and how to hook it again after fixing the cable?
Thanks
Can you do mine 🙂
Thanks for this….helps alot…..took both seats out and got 1 seat working, but unfortuantely the drivers side still has the twist w about 1/4 a 1/2″ of the wire reinserted into the motor…..any other thoughts? The only one i have is that one of the moters needs to be replaced
Thanks fixed my seat!!
Can anyone fix for me ?
First of all, not easy. Second, dont you think putting down some of the sizes of tools and heat shrink that was used would be helpful? Guess not since you didnt put it in. And how about which motor operates what? Jesus Christ I curse the day i found this diy on the top of my google search. I want those several hours of my life back buddy….
Gosh Steve, how ungrateful. Where”ks your DIY listing the tools and other items you mentioned. You tried a DIY project and thought it would be easy???? And wouldn’t take hours?? And you want to blame this guy for that time? Obviously you don’t have much DIY experience. Imagine how long it would have taken you without this guide.
Fuck this diy. I want those several hours of my life back buddy….
This is an awesome write up! My passenger seat just twisted for the first time yesterday. Very annoying let me tell you just kept getting worse when i tried to keep playing with the buttons so i left it alone, i will definetly be doing this and hopefully my issue gets fixed! My driver seat doesnt go full movements as well so hopefully doing this fixes that too and i wont have to dip into the more serious electricals and new motors etc! Thanks!
Awesome, thanks. Helped out a neighbor. By the way, in his 2003 525i the cable was present under the drivers seat. You picture really saved me, on getting it reattached.
Nice blog.
I keep seeing others mention to ensure you disconnect the negative cable from the battery before unplugging the seat connector. Is that required? What occurs if you do not?
Where are u located ?
I’ve been told bad gearbox is causing the twist in my seat back. How many gearboxes are there? Only one??