Thermo Time Switch

[wwheeler]

I have a couple questions about the stampings on the TTS. Looking at the tech manual, it almost matches my original 2/68 date code. One thing is different. Mine says 93*C +/- 3*. I am assuming that is similar to the 120*C max in the tech manual and should be OK.

Now for the new one I have. It is date coded 10/07 and has the same 20*C @ 9.5 sec but has 40W instead of 3W. I assume I just can't see the decimal place and is 4.0 W. Still a little different but everything else is the same. Now the new piece of info on the new part not present in the tech manual is stamped just below the 120*C max. It reads 36/2/9. What does that mean?

Also, are there different models that switch off at a higher temps than say 35*C? Hoping to get one around 50*C.

Thanks for the help!    

[ctaylor738]

I don't see where you are getting the 93C and 120C numbers in the discussion about the TTS in the manual.  These numbers sound like they refer to a maximum running temperature for a sensor that might be used to cut off the AC compressor when the engine gets really hot.

I believe that the 20*C @ 9.5 means that the switch will remain closed (i.e. providing ground to the relay) for 9.5 seconds when the coolant temp is -20C.  I am looking at 07-14, page 10 in the tech manual.

I don't think that the reference in the manual to a coolant temp of 35 is for a cut-off.  It's more for engagement.  It means that the switch won't close and provide ground at 35 or higher.  If you start the car at -20C, the TTS will cut off the CSV after 9.5 seconds of cranking.  At that point the coolant temp would still be -20.

And, sorry, don't know if there are any switches that will engage at temps higher than 35.  Mercedes tried to resolve this issue with the hot-start relay that fired the CSV for a second or two regardless of engine temp.

Hope I didn't muddy the (cooling) waters.

CT

[wwheeler]

Thanks Chuck.

I did find another TTS. #001 545 15 24. It is a weird one though. It stays on longer, - 20*C for 12 secs.  But the temp when the points open is 5*C (41*F). I didn't believe it so I put it in the freezer. At room temperature, there was no continuity (points open). After being in the freezer for 15 minutes, it had continuity meaning the points were closed. If I had that one in Dallas, it might come on once a year. It must be for some place like Siberia.