Replacement Thermo-Time Switch Alternatives?

[JamesHigdon]

I have found my thermo-time switch is bad and I'm looking at options to replace it; I have found that many European cars used switched similar to the Pagoda up into the 80's and those switches are still available new locally. Has anyone experimented with a thermo time switch off a later model car?

http://www.ebay.com/itm/Mercedes-Benz-Thermo-Time-Switch-230SL-250SL-280SL-220SE-250SE-280SE-0015459224-/251916935265

It is obviously possible as that is all this is; thing is I can buy these switches for $15-20 locally I just need to figure out which one it is!

[Tyler S]

You need one that opens at 35 deg celsius and above. The others you mention are a normally open design. The w113 TTS is a normally closed design. The one used in the later 107 chassis function the same however they open at 15 deg celsius and wont work for the w113. A regular thermal switch from the 80's wont work because it is not a "time" switch. It cuts in or out based on temp only. Your choices are pretty limited to what you have found. Another vendor has the same type of kit.
http://www.authenticclassics.com/Mercedes-Thermo-Time-Switch-230SL-250SL-280SL-p/auth-006760.htm

An original type retails for over $900 so the buds benz or auth classics replacement is a good alternative.

[Jonny B]

James,

In the technical manual, take a read of Pagoda Notes, Volume 2, Issues 2 and 3 there is a discussion about the thermo time switch and its function.

[Shvegel]

Pretty sure the 80's Bosch CIS cars(VW Golf, Saabs. Volvo's audi"s and Ferrari's etc) were temperature and time related as well.  they provided ground to the cylinder head for the cold start injector on one terminal and the second terminal was for supplied power that activated a heater which shut the ground off.  All based on a sliding scale of temperature and length of time the heater was energized.  You will have to dig up specs but there have to be used ones around by the handfulls.

[ja17]

They original used ones are becoming scarcer.  Sometimes they go bad, but most often they are ruined while trying to remove stubborn, rusted screws holding the wires.

[Naj ✝︎]

There is a Bosch switch as used on some Porsche and VW models.
Bosch have recently started remaking them.
The part # is F 026 T03 101. 12V/35 Degrees C/12Sec.
The plug is Bosch # 1 284 485 110
The terminals MB 003 545 0226. Sorry, don't know the Bosch #

naj

[JamesHigdon]

The ground in my thermal time switch is present when cold but very weak and as soon as power is put to it I see that power through the switch so it's bad. My main goal in trying to find an alternative thermal time switch is that I hate relying on obsolete parts to keep vehicles running; yes I could pay $900 for a NOS switch but eventually that supply will dry up; if I can find a later model switch that is now made by someone like Beck and Arnley or Wells then I will have a long-term supply of that part. Ground vs Power input doesn't matter, one can run a relay to switch signal. I'm in San Antonio TX where the average summer temp is 35*C or higher so running a 15 or 20*C switch won't work, I wonder if older diesel systems with cold start injectors used a similar switch?

[Tyler S]

James, here is a page from Bosch. You can use this to cross reference the switch to another make. Looks like Citroen Renault BMW etc used the same part. You might be able to look up/find an aftermarket unit designed for one of those cars. Should technically work since its a replacement unit for the original part number. I looked a few up and there still upwards of $180
http://www.bosch-automotive-tradition.com/en/internet/automotive_tradition/parts/reproduction/motor/thermozeitschalter_1/thermozeitschalter___mit_teaser.html