'95 E320 wagon (124) has "Snow Chain Mode' switch. WHat exactly does this do?

That would be an ASR equipped car - anti-slip regulation. The ASR system needs to be told that you have snow chains on the car. Your Owner's Manual explains more.

Paul, the Snow Chain mode provides maximum possible traction at speeds up to 25 mph. It remains stored in memory up to 37mph and automatically engages again when the vehicle speed drops below 25 mph. The mode is canceled in memory above 37 mph and the indicator lamp in the switch goes out. See Page 77 of your Owner's Manual.

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Fred Hoelzle

the Snow Chain mode provides maximum possible traction at speeds up to 25 mph

Anybody know exactly how it does that. Does it allow limited wheel slip? If so is it a percentage of front wheel rpm? Does it prevent one side from slipping if the other side is grabbing--maybe by applying brake to the slipping side?

In other words, just exactly what does it do and how does it know to do it?

Thanks.

J. M. van Swaay

That sounds more like a description of ASR rather than the snow chain mode. The snow chain button is just a way of partially deactivating ASR. ASR is so vigilant about avoiding wheel spin that sometimes with snow chains in heavy snow it prohibits the car from moving at all. Depressing the snow chain button allows for a little more wheel spin.

It also allows the torque limitations for ASR to be overridden up to 25 MPH.
The idea is they want the tire to spin a little b/c of the disatance between chain links.

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A Dalton

Aha! Thanks.