Driver's Seat ECU

Talk about the 406's electrical system, what wires do what, how to add extra functionality, etc.

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Driver's Seat ECU

Post by Sage103 » Tue Nov 07, 2017 12:12 pm

This is only week2 of my 406 adventure but it came with a fault which I really need to crack - the driver's seat (it's an Executive estate) doesn't move in any way. Passenger seat is fine. Fuses are good. Can anyone suggest the likely cause? Faulty ECU? Or faulty switch? And given that the Haynes manual is fairly useless in this particular area can someone point me towards the ECU? I've seen the post regarding bypassing the ECU but I think I'll leave it if all else fails.

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Re: Driver's Seat ECU

Post by Doggy » Tue Nov 07, 2017 1:43 pm

Hi & welcome aboard. 8)

Not heard of any similar problems. Mine had the up/down not working on the driver's seat when I got it, (but the motor was operating). That was a detached flexi-drive that just clipped back in.

IIRC the motors are all essentially the same, but those on the drivers seat have position encoders and the passenger seat doesn't. Maybe you can connect a plug from one side to the other to narrow it down?

The ECU lives under the driver's seat.

If you memorise the positions, (press/hold button 1 or 2 until it beeps), then adjust your door mirrors do they go back to the memorised position when you press the button a second time?
2002 HDi 2.2 Exec Estate, (2008-12)
2003 HDi 2.2 6-speed Exec Estate (2012-19)
2009 Citroen C5 2.0 HDi VTR+ Estate

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Re: Driver's Seat ECU

Post by GingerMagic » Wed Nov 08, 2017 11:20 pm

Check your mirrors first.
If the mirrors or mirror switch is unplugged or a broken connection then your drivers seat will not work.

You can get a switch from a non-exec and plug it into your seat ( big orange connector, just leave the switch connected but just hanging down ) which will bypass the memory ECU and allow you to move the seat until you find a fix.
1999 T4 family wagon
2005 Vauxhall Meriva
1998 406 V6 Coupe - Midlife crisis..!
PP2000 user, can help with faults / diagnostics in the Bournemouth area.

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Re: Driver's Seat ECU

Post by Sage103 » Sat Nov 11, 2017 10:46 pm

Thanks for these replies. The mirrors are also dead so bypassing the ecu with a non-exec switch looks promising. Coincidentally the nearside mirror has been pranged so maybe worth checking its internals when daylight returns. Meanwhile I have ordered an ecu off eBay but I'll just keep that in reserve for now.

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