Faulty Drivers Seat electrics?

UK forum for general and technical discussion about the Z3 roadster
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bartholomewzman
Joined: Thu 27 Jul, 2023 19:05
Posts: 6

  Z3 roadster 1.9

Faulty Drivers Seat electrics?

Post by bartholomewzman »

Time to ask for advice please?
The Drivers Seat works fine moving Forward, and also Up and Down, but has just stopped moving Backwards (so making is hard to drive at the moment as my wife left the seat in the position of me having my sternum way too near the wheel !!!) The Switch been working ok up to now, but am wondering if it might be something just gone wrong with the 'Button' used to allow the backwards operation?.
So the query simply is - Is this a common fault with a straightforward 'cure' please, which would hopefully save me trying to 'explore' the wiring? (I am presuming that it wouldnt be simply a fuse issue as so much of the seat mechanism is still working fine)

Ideas/suggestions welcomed!

Cheers all, and happy Summer motoring,
Richard (ps: I may have recently put this query into the wrong section, so trying again here!! Driving the car at the moment makes me look like I am hugging the wheel like a passionate "lover"!!)
LaRy
Joined: Mon 12 Nov, 2018 17:47
Posts: 158

  Z3 roadster 2.8

Re: Faulty Drivers Seat electrics?

Post by LaRy »

First, I need to know manufacturing year and if you have sport seats. The sport seat electrics is more complicated.
If you have a standard seat, it is simple. The direction, polarity of the motor is all done in the switch. If the motor is working in one direction, it must be working in the other direction, if the contact is made in the switch. If not, broken switch.

But in the sport seat, it is more difficult with end limit switches and also a cut-off relay in the seat that can be broken.
So please comeback with some more info.
bartholomewzman
Joined: Thu 27 Jul, 2023 19:05
Posts: 6

  Z3 roadster 1.9

Re: Faulty Drivers Seat electrics?

Post by bartholomewzman »

Hi LaRy, Many thanks for reply - the car is a 1998 standard 1.9 and I think the seats are standard too. I take your point about the switch should be working so looks like I will need to examine the Button and see if I can take it 'off' to check it. Alternatively will need to check the main Switch contacts to see what's changed inside..( I fear that that that may mean taking the seat out completely to get at it from the inside?, but will try to look over the weekend)
It was working fine, as my wife liked to drive,but is much shorter than me, so the seat did get some use back and forth!!

Any further suggestions welcomed, Cheers, Richard
LaRy
Joined: Mon 12 Nov, 2018 17:47
Posts: 158

  Z3 roadster 2.8

Re: Faulty Drivers Seat electrics?

Post by LaRy »

If you have the standard seat, you can check the passenger seat to confirm. When driving forward or reverse hitting the mechanical movement limits, the motor should not really stop, it will be to heavy to continue to drive.

All the logic is in the button, simply reversing the polarity. If it can work in one direction, the contact must be broken for the opposite direction. To make it clear, the electric motor can never be broken in just one direction.
The fact that the height motor is working, is also showing that all the electric supply is ok.
Go for the switch!

I found some info how to remove the switch: https://zroadster.org/threads/remove-th ... itch.6555/
bartholomewzman
Joined: Thu 27 Jul, 2023 19:05
Posts: 6

  Z3 roadster 1.9

Re: Faulty Drivers Seat electrics?

Post by bartholomewzman »

Hi, I plan to get onto it tomorrow once work on the house window painting is hopefully finished. Must make the best of the weather - in this country you just never know!
Thanks again,
bartholomewzman
Joined: Thu 27 Jul, 2023 19:05
Posts: 6

  Z3 roadster 1.9

Re: Faulty Drivers Seat electrics?

Post by bartholomewzman »

Hi LaRi.
Guess what? I struggled to try to take the seat out to get at the back of the Switch and Button electrics - and lo and behold, there was a 10amp Fuse 'dangling' tucked away underneath. Yes - - it was blown, and once replaced the seat seems fine. Whether it may blow again remains to be seen, but at least I am a little less likely now to crush my sternum should I brake too hard!!

So Folks - - another lesson learned. If your seat stops working then go for a fuse underneath first - - and note that the only thing it controls is the Drivers Seat 'Backward' operation, as all else still works fine..
Thanks all, Richard
LaRy
Joined: Mon 12 Nov, 2018 17:47
Posts: 158

  Z3 roadster 2.8

Re: Faulty Drivers Seat electrics?

Post by LaRy »

bartholomewzman wrote: Tue 02 Jul, 2024 13:59 Hi LaRi.
Guess what? There was a 10amp Fuse 'dangling' tucked away underneath. Yes - - it was blown.

So Folks - - another lesson learned. If your seat stops working then go for a fuse underneath first - - and note that the only thing it controls is the Drivers Seat 'Backward' operation, as all else still works fine..
Thanks all, Richard
It is good that it is working! :shock: But I have been looking in all electric drawings, standard and sports, and it should not exist any 10 Amp fuse down under the seat. Not a fuse for any other purpose either. I've even been looking under my seat, no fuse. But I'm happy for you that the problem is solved.
bartholomewzman
Joined: Thu 27 Jul, 2023 19:05
Posts: 6

  Z3 roadster 1.9

Re: Faulty Drivers Seat electrics?

Post by bartholomewzman »

Yes, I couldn't see any Fuse in the circuit diagram, but it's there and they seem to be the only wires (both red) that are going to the small seat 'Button' for Fwd/Rev operation. Wihtouit taking the seat out to see underneath better they appear to be the only electical wiring going to that button.
I wonder if in the past there has been a seat problem, and someone has 'added' to the circuitry??
Thanks again, Richard
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