Mercedes W163 Locate a Parasitic Battery Drain (Tele-Aid Emergency Call circuit, Fuse 8) ML350 ML500

This video shows the step-by-step process for confirming and locating the source of a parasitic battery draw (drain, leak) on the W163 (ML320, ML350, ML500). A parasitic drain was discharging the battery on this '05 ML500 such that it wouldn't start after just a couple days sitting. The cause was determined to be the Tele-Aid module, which is an obsolete emergency call system that MB has not supported since about 2007/2008.

The steps in the first part of this video are general to any parasitic drain and show the techniques for confirming and locating the trouble circuit on the W163.

The latter part of the video shows troubleshooting of the Fuse 8 circuit and Tele-Aid circuit in particular.

Timestamps and Links:
*Find the parasitic leak:*
00:38 Use a multimeter to detect current at the battery
05:19 Use a multimeter to detect voltage across Fuses
10:04 Check fuses in the interior fuse box

*Troubleshooting the problem circuit (Fuse 8):*
14:00 Troubleshooting the Fuse 8 circuit
18:41 Checking current at the battery with Fuse 8 removed
20:44 Remove the front seat to reach the Tele-Aid module
21:51 Disconnect the Tele-Aid module
22:42 Checking the Fuse 8 circuit with the Tele-Aid module disconnected
24:01 Tele-Aid circuit diagram
27:57 Inspecting the Tele-Aid module
28:06 SRS light shows with the Tele-Aid module disconnected

*Repair options for the Tele-Aid circuit:*
29:23 Important information about repair options
32:46 Disconnect the overhead Tele-Aid switches ("SOS" switch)
34:17 Inspect the Tele-Aid switch board
37:18 Re-install the Tele-Aid switch
38:32 Checking voltage on Fuse 8 with the Tele-Aid switch disconnected

*Installing the replacement Tele-Aid module:*
39:06 Remove Fuse 8 before installing the replacement Tele-Aid module
39:32 Remove four 10mm bolts to remove the module
39:40 Comparing the old and replacement modules
40:25 Reconnect the Tele-Aid module
40:57 Checking voltage on Fuse 8 with the new module installed
41:16 Checking and clearing SRS codes
42:07 Re-install the seat
42:41 Checking current at the battery

Here are some links mentioned in the video:

Humble Mechanic's video on parasitic draws:
https://www.youtube.com/watch?v=lRcj1fQcWwU

Voltage Drop Fuse Charts:
https://www.powerprobetek.com/wp-content/uploads/2018/12/fuse-charts.pdf

Alternator diode testing:
https://www.youtube.com/watch?v=oUhgyqm0wro

Removing the alternator on the W163:
https://www.youtube.com/watch?v=qeSMEd1w93k

I hope the video is helpful. Thanks for watching, and good luck with your repair!

Видео Mercedes W163 Locate a Parasitic Battery Drain (Tele-Aid Emergency Call circuit, Fuse 8) ML350 ML500 канала L35 in Colorado