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Old 05-25-2019, 04:20 PM   #2
autostaretx
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Default Re: TCM Radio/Data-line Connector wire in stereo harness

The original Becker radios in the US-delivered T1N Sprinters use the "speed sense" wire to increase volume as you go faster (countering the louder road noise).

It's a pulse whose frequency increases with speed. If memory serves, you get about 1000 pulses per mile.
(so at 60 mph you get 1000 pulses per minute, or 16.7 pulses per second)

According to the T1N service manual, the speed sense wire was a 20 gauge Blue/Red/White wire to pin 9 on the connector.
It's the only 20 gauge wire MB fed to the radio.

--dick
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2005 T1N 118" Freightliner 2500 Passenger Wagon (2.7L, 15" tires, standard (short) roof)
Get YOUR Sprinter's full configuration datacard by entering your VIN to https://www.datamb.com/
http://diysprinter.co.uk/reference <-- lots of service documentation, Thanks to Jens Moller and Arnie_Oli
((as always: this post may go through a couple of post-posting edits... so maybe give it ten minutes before commenting))
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