Interior - Pneumatic 4-Way Lumbar Support Fails

2010 Mercedes Benz Truck GL 350 BLUETEC (164.825) V6-3.0L DSL Turbo (642.820)
Vehicle: All Technical Service Bulletins
Interior - Pneumatic 4-Way Lumbar Support Fails
Failure of pneumatic 4-way lumbar support
Topic number LI91.10-P-048411
Version 3
Design group 91.10 Front seats
Date 09-21-2012
Validity Model series 204, 212, 218, 207, 164, 251 with pneumatic lumbar support!
Not valid for code 409 or 432 (multicontour or dynamic seat)
Reason for change Part number for pressure tester corrected
Complaint:
The pneumatic 4-way lumbar support fails.
Lumbar support pockets cannot be filled up or they drain.
(Lumbar support on multicontour seat / dynamic seat not affected!)
Cause:
Component defect in lumbar support control unit.
Remedy:
Precise fault location:
Check whether the air pockets exhibit a leakage before replacing any components.
1. Remove tensioning element of affected seat
2. Cut through red and yellow air lines at a point 5 cm after the connector (see IMG_2157)
3. Connect pressure testers one after the other at the red and yellow line
4. Fill each one with maximum of 300 mbar
5a. If pressure drops within 30 sec one of the pockets is defective and the complete lumbar support module has to be replaced
5b. If there is no pressure loss detected, then the lumbar support parts kit is generally to be used
Install pump and control unit:
Replace control unit and pump as follows
^ Disconnect blue line on control unit using special tool W000589043700 (see IMG_2154)
^ Release electrical connection (see IMG_2155)
^ Detach fastening clips (see IMG_2156)
^ Install new control unit (see IMG_2159); when doing so push brass connectors onto the air lines as far as they will go (see IMG_2160)
^ Disconnect electrical connection on the old pump
^ Unhook spring of wire suspension (see IMG_2158) and slide pump, together with foam bag, off the wire
^ Slide new pump onto the wire (see IMG_2161)
^ Reattach wire suspension and position the pump correctly
^ Connect blue pneumatic line to the control unit (see IMG_2160)
^ Re-connect the electrical connections of the pump and control unit
2010 Mercedes Benz Truck GL 350 BLUETEC (164.825) V6-3.0L DSL Turbo (642.820)
Page 2
^ Perform a function test; when doing so check for leaks and noise in the pump. If necessary, re-position the pump
^ Complete re-assembly of seat
Important:
Always fit a new control unit and pump.
Attachments
Symptoms
Parts
Work units
Attachments