E320 Power Seat Problem-Weird
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Joined: Nov 2006
Posts: 13
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E320 Power Seat Problem-Weird
Hi all,
I have a 1999 E320 with 2very strange power seat problems. I need help!!
On the passenger side, the seat controls on the door seem to work when they want to.It started with theupper backseatcontrol. It wouldn't recline the upper portion of the seat but would go up. (had been working fine in both directions). BUT...when youpush the memory seat buttons,the upper seat back will recline and go up just fine.A week or so later, I push theswitch tolet theentire passenger seat back, and it doesn't work!!! But it will go forward just fine!Again, when I use the memory seat buttons the seat will go back and forward. To make it a little more difficult, now the upper back seat button decided to work.Itreclines the seat and moves itup again just fine. I don't get this. Why does this seat control work in different positions part of the time?What would make the memory buttonswork?All theother positions work fine. Just when I hit the switch now, the entire seat won't go back at all and I hear a click....but will go forward just fine and will go back at least when I press the memory buttons.
I am so frustrated and each time I hit the switch I don't know what will be working. Very irritating to my passengers that need the seat pushed back.
Does anyone out there know what might be causing this and why???? I don't want to go to the dealer as the dealer in my area is known for ripping people off and charging for things that aren't needed. Any help is appreciated.
Thanks
I have a 1999 E320 with 2very strange power seat problems. I need help!!
On the passenger side, the seat controls on the door seem to work when they want to.It started with theupper backseatcontrol. It wouldn't recline the upper portion of the seat but would go up. (had been working fine in both directions). BUT...when youpush the memory seat buttons,the upper seat back will recline and go up just fine.A week or so later, I push theswitch tolet theentire passenger seat back, and it doesn't work!!! But it will go forward just fine!Again, when I use the memory seat buttons the seat will go back and forward. To make it a little more difficult, now the upper back seat button decided to work.Itreclines the seat and moves itup again just fine. I don't get this. Why does this seat control work in different positions part of the time?What would make the memory buttonswork?All theother positions work fine. Just when I hit the switch now, the entire seat won't go back at all and I hear a click....but will go forward just fine and will go back at least when I press the memory buttons.
I am so frustrated and each time I hit the switch I don't know what will be working. Very irritating to my passengers that need the seat pushed back.
Does anyone out there know what might be causing this and why???? I don't want to go to the dealer as the dealer in my area is known for ripping people off and charging for things that aren't needed. Any help is appreciated.
Thanks
Senior Member
Joined: Dec 2004
Posts: 2,410
From:
RE: E320 Power Seat Problem-Weird
Hi,
The seats are controlled digitally. Not the "old fashioned" conventional way with a wire for each function controlled. this would need lots of wire to go between the switch and the seat. (Heavy, cumbersome and expensive. Instead just two lightweight wires like a computer network are used)
Digital systems can give VERY complex symptoms due to the way they work. Basically when you operate the switch a code signal is sent down the wire like the keyboard on your computer. If there is a "bad" connection or faulty component the signal can become corrupted making one signal appear like a different one leading to an "incorrect" response to the signal. The usual symptom is the very random nature of the response to a given input. e.g. You press the brake and the flashers work oir the radio switches off.)
Digital controlled circuits need diagnostic tools to help resolve problems (only available at MB main dealers).
However I would try the following.
Inspect the connection between the wiring harness and the door switch, Sometimes this connection can corrode (my experience is cleaning solutions inc water that are used when the vehicle interior is valeted, If not it may need a new switch BUT it could also be the receiving module under the seat OR in fact anything else plugged into the digital highway.
Switches appear regularly on eBay at affordable prices.
Working on digitally controlled circuits is not a DIY type project I'm afraid.
Stuart
The seats are controlled digitally. Not the "old fashioned" conventional way with a wire for each function controlled. this would need lots of wire to go between the switch and the seat. (Heavy, cumbersome and expensive. Instead just two lightweight wires like a computer network are used)
Digital systems can give VERY complex symptoms due to the way they work. Basically when you operate the switch a code signal is sent down the wire like the keyboard on your computer. If there is a "bad" connection or faulty component the signal can become corrupted making one signal appear like a different one leading to an "incorrect" response to the signal. The usual symptom is the very random nature of the response to a given input. e.g. You press the brake and the flashers work oir the radio switches off.)
Digital controlled circuits need diagnostic tools to help resolve problems (only available at MB main dealers).
However I would try the following.
Inspect the connection between the wiring harness and the door switch, Sometimes this connection can corrode (my experience is cleaning solutions inc water that are used when the vehicle interior is valeted, If not it may need a new switch BUT it could also be the receiving module under the seat OR in fact anything else plugged into the digital highway.
Switches appear regularly on eBay at affordable prices.
Working on digitally controlled circuits is not a DIY type project I'm afraid.
Stuart
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