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· Registered
137 Posts
Discussion Starter · #1 ·
If your power seats crap out on you, the part that fails inside is BTS409L1

This is what controls the input on the ecu telling it what to do. The relays are generally never at fault. This switch handles the grunt and grind of everything coming into the unit and therefore can tend to fail after a few years.

You can see the PDF for this part here:

You can see the burnt leg and tracers around the unit. Once you replace this and verify the tracers are back in order, your seat ecu should function well.


· Registered
1987 300E (sold) , W203 C320 2001 (09/2013), W210 E320 1999 wagon 4matic (10/2013)
115 Posts
Need more informations

Would like to know more about the procedure ...

I'm french so the term "verify the tracers are back in order"
What do you mean ?

BTS409L1 can be found on E Bay for about $4-5

· Outstanding Contributor Always Remembered RIP
216 with everything. 2002 SL500 with everything. 2009 SL500 with everything.
6,613 Posts
That PCB has had water damage hence the blue stains, I have never heard of the tracks being called tracers, but there we are.

· Premium Member
2004 CLK 240 Coupe
11,408 Posts
Guys (and mods)

I have no idea what this 7-year old thread is about. As far as I can tell. it has no relevance to W208 models. If so, this information is useless here.

The OP does not refer to MB - or any particular module apart from the 'ECU', which has nothing to do with seat motor control on W208. Also there are no relays involved in the W208 seat motor control.

W208 has seat control group switches (S91/1, S91/2) as inputs to the left/right front ESA control modules (N32/1, N32/2). Outputs from those modules are taken directly to the various seat control motors.

N32/1, N32/2 modules are located under the respective seats.
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