1965 230 SL Thermo Time Switch Test

[Klaus Pieper]

Hi,
In the Technical Manual - Engine Starting Aid Manual under the Thermo Time Switch Testing section it reads, "next re-hook your test light to the positive post of your battery and test to se if the "W" terminal is grounded and illuminates your test light when the temperature is below the set temperature shown on your switch (usually 35 degrees C), that is when starting the cold engine." 
When I performed the test, the test light already illuminated when I turned the ignition key on, but before I cranked the cold engine, and remained illuminated whilst I cranked the engine.  Is this correct?
By the way, the verifying test and the other test for TTS were all in order.
Thank you for your help.

[Pawel66]

When the engine is cold, W should be grounded. Regardless of the key position. If you hooked the test bulb to battery - it should light up immediately, if after ignition, it will light up when you turn the key to ignition - does not matter, as long as W is grounded, which it should be with cold engine. In real work, not test conditions, G is powered when cranking, but for the test if W has the ground, it does not matter.

[ja17]

Yes, determine if you have starting aids version II or III. Refer to the chart for your version to see at what engine temperatures your starting aids should activate. The TTS supplies ground (earth) to activate these starting aids at the charted temperatures. As Pawel mentions, the power + is supplied to the system any time the ignition switch activates the starter motor.

[Klaus Pieper]

Thank you very much Pawel and Joe for your help.  I have starting aids version III.