I am reposting this after getting some clarifications and corrections from Joe and Bob. Thanks again to each of you.
After studying the wiring diagram for a later 1966 230SL (Version III) and hearing from others on this forum, I think that I have captured the gist of the Starting Aids for this car. I am posting it for future reference here perhaps in a more clear and succinct manner for those who may be early in trying to understand the approach used by Mercedes. I made a labelled excerpt from the wiring diagram that I believe supports this summary, but I am always happy to hear from others to achieve factual accuracy.
I did not elaborate on how the individual components that make up this system operate since that is provided in the tech manual.
Involved components
Starting Aids
1- Cold Start Valve (CSV) 31
2- Fuel Enrichment Solenoid (ES) 33
Supporting Electronics
3- (Ignition switch/starter)
4- Thermo-time switch (TTS) 32
5- Time switch (TS) 20
6- Starting Relay (SR) 21
How It Works
When the ignition switch is turned and held in the Start position, 12v is provided:
- To the Time Switch (20) – provides a ground to the SR for about 1 second
- To the TTS (32), - provides a ground to the SR for about 9 seconds (on a cold engine), and
- To the electromagnet of the Starting Relay (21) – when ground is provided, provides power to the CSV (31) and ES (33)
The Starting Relay (21) electromagnet closes the primary circuit of the relay sending the 12v from Fuse 6 to both starting aids – Cold Start Valve (CSV) (31) and Fuel Enrichment Solenoid (ES) (33). But - for that to happen, the electromagnet in the Starting Relay (21) must be grounded.
This ground circuit for that electromagnet is simultaneously provided through both the Time Switch (20) AND the TTS (32). But the ground circuits are only temporary - so those start aids will only operate for a brief period with each start attempt.
When the Time Switch (20) receives its 12v from the ignition switch, it drops its ground after about a second or so. After the ground from the Starting Relay (21) is lost, the ground from the TTS (32) is still provided to the Starting Relay (21) and both start aids will continue to operate.
When the TTS (32) also receives the 12v from the Starting Relay (21), it drops it ground, but in about 9 seconds. (The duration of time the TTS requires before it drops its ground connection is dependent on engine temperature. A cold engine will take longer to drop ground than a warmer engine.)
When both grounds to the SR are dropped, the starting aids are no longer powered.
So – since the TTS operates for the longer period of time on a cold engine, it is the dominant factor in starting a cold engine and will provide starting aid support for up to about 9 seconds. (Multiple start attempts may have a shorter application of the aids since the TTS will have been warmed up on prior attempts.)
An engine that is already at running temperature will not benefit from the TTS (32) ground since it will already have been dropped by the warm engine temperature. Under those conditions, the TS (20) will continue to operate (for about a second) and becomes the dominant factor in starting. As a result, the CSV and ES will operate very briefly even on starting an engine at running temperature.
