230SL Time-lag switch - how does it function?

[66andBlue]

The early and late 230SLs have a "Time-lag Switch" (that is its name in the parts list, but also known as "time switch" or "1-second switch"; MB p/n 001 545 16 24 or Bosch SH/VT2/12/2). It is a round black relay with three pins and usually located next to the washer fluid bag on the engine bay wall. According to the wiring schematic in my owner's manual (late 230SL) it is normally in the closed position, that is, ground pin 31 is connected to pin 85.

I assume the relay opens when the starter is activated, but for how long? How is the lag-time determined?  I am hoping one of the electrical wizards here can enlighten me.


Thanks!

[Jonny B]

This topic is covered by Joe A in his starting tour. This was also the subject of the last two issues of Pagoda Notes. The time lag switch activation duration is dependent on the outside temperature. The tour will give you more information on the whys and hows. Go to the search function and search on "tour" in the subject line, not the whole message.

[66andBlue]

Hi Jonny B,
I did read those articles and the tour and know what it does but my question is how?
What happens internally when voltage is applied from the ignition key?
What happens internally when W on the TTS goes to ground after the temp is reached, and before the set temperature is reached? Etc.  :?:  :?:
--
Oops, just noticed that this thing is actually described in the manual in the engine section: http://www.sl113.org/wiki/pmwiki.php?n=Engine.TimeSwitch
Now I need to figure out how the TTS comes into play.