Thermo Time Switch

[toneypenna]

64 230 SL:

My  thermo time switch needs to be replaced.  As you know replacements are not available. I have a Bosch # F026T03101 which  they claim is a viable replacement option with a little alteration to the wiring which is no problem.
I've searched the forum and technical manual and have seen some discussion on  this switch, however I have come up with nothing regarding which wire goes where. Did I miss something? The switch is not marked positive and negative (ground) as is the original. There is the # 037 at the plug end, see picture attached. I called Bosch Tech line and as usual with todays customer service, I never heard back. If anyone has done this or can advise, I would greatly appreciate it.

Jim

[Pawel66]

Enclosed.

I posted it before, I think, but it may not be easy to find.

When you enter Bosch system with the part number, you can get to product info that provides this kind of data.

[toneypenna]

Thank you so much for this.


I don't have the connector for the switch I just put corresponding female connectors on the two wires with heat shrink  on each to prevent any arcing or grounding. I didn't want to attach the wires until I knew for sure which went where.
I'm assuming the  plug connector is specified as the terminal on the spec sheet, part# 1 224 485 018. I will be looking into getting one so it will alleviate someone in the future in advertently crossing the wires.

Still can't understand why Bosch doesn't mark the switch with a simple + and - to denote the terminals.  Grasping at straws, could the 037 that appears painted  on the switch have something to do with that , the 0 meaning negative ??

Again your input is greatly appreciated.


Jim

[BobH]

Hello, some pictures and details of the TTS connector on here

https://www.sl113.org/wiki/Engine/ThermoTimeSwitch?action=download&upname=W113%20Cold%20Start%20Thermo%20Time%20Sensor%20Alternative%20rev%201.pdf

[Pawel66]

Thank you so much for this.


I don't have the connector for the switch I just put corresponding female connectors on the two wires with heat shrink  on each to prevent any arcing or grounding. I didn't want to attach the wires until I knew for sure which went where.
I'm assuming the  plug connector is specified as the terminal on the spec sheet, part# 1 224 485 018. I will be looking into getting one so it will alleviate someone in the future in advertently crossing the wires.

Still can't understand why Bosch doesn't mark the switch with a simple + and - to denote the terminals.  Grasping at straws, could the 037 that appears painted  on the switch have something to do with that , the 0 meaning negative ??

Again your input is greatly appreciated.


Jim

I should have added for clarity:
+ on the Bosch unit diagram is equivalent of G on original
switch symbol on the Bosch unit diagram is equivalent of W on original
Ground is on housing

I would have thought that in modern cars just plug with wires goes in it - that is all. If there is a need to figure out which connector is which - technicians can look it up. This part may go in many different places to be used in many applications, each od them having different markings...

[Pawel66]

Hello, some pictures and details of the TTS connector on here

https://www.sl113.org/wiki/Engine/ThermoTimeSwitch?action=download&upname=W113%20Cold%20Start%20Thermo%20Time%20Sensor%20Alternative%20rev%201.pdf

This is great! Deserving place in Technical Manual.

I would just be careful calling W connector "ground". Probably "ground signal" would be true...

[Bshaunessy]

TONYPENNA
 I just replaced my Thermo Time Switch with the BOSCH TTS you are referring to.  Similarly, I had some confusion RE "W" and "G? terminals and which is which.   See pic below sourced from BUDS BENZ website ( TTS is located EXHAUST section???)
or this link https://www.budsbenz.com/catalog/230-250-280-sl/g-exhaust-parts-intake-system/G207-013

[toneypenna]

Thank you for that information and additional diagram from Buds Benz. Very helpful.

Jim

[toneypenna]

Pawel

Thank You for the follow-up. When your not sure, as I am , all of this info is very helpful.

Jim

[toneypenna]

Bob H

Thank you for your input, most helpful

Jim

[Bshaunessy]

TonneyPenna
 (1) a Bosch F026T03101 TTS from BUDS ($259) also comes with the plug and boot to fit the TTS connections.   They might be able to just sell you the plug and boot if you already have the TTS from elsewhere?

(2) strongly suggest you bench test resistance "G" to ground, "W " to ground , with and without 12 v applied BEFORE installing in car.  ( proper ohm readings in the TECH Manual) .  The first TTS i received was defective. 

[toneypenna]

TonneyPenna
 (1) a Bosch F026T03101 TTS from BUDS ($259) also comes with the plug and boot to fit the TTS connections.   They might be able to just sell you the plug and boot if you already have the TTS from elsewhere?

(2) strongly suggest you bench test resistance "G" to ground, "W " to ground , with and without 12 v applied BEFORE installing in car.  ( proper ohm readings in the TECH Manual) .  The first TTS i received was defective. 

Bshaunessy
Thank you for the Buds Benz tip, I already have the switch, I'll see if they will sell just the wired plug and boot. I installed the switch and still don't get power to the CSV in start mode. I put power to the pink wire and the relay clicks, Ran a test light from power to pink/blue and it lights so I have ground. Possibly a bad switch as you mentioned.

Don't fully understand how to test as you described, I'll have to read up on it.
Thank you for your help, much appreciated.

Jim

[Pawel66]

I would have thought I would check if everything else works in the cold start system - provide ground to relay where normally ground comes from TTS, crank the engine and see if CSV gets power.

If yes - it is TTS or its wiring. If not, something else may not work.

[toneypenna]

I would have thought I would check if everything else works in the cold start system - provide ground to relay where normally ground comes from TTS, crank the engine and see if CSV gets power.

If yes - it is TTS or its wiring. If not, something else may not work.

Pawel

You are right, I put ground to the relay and I have power to the CSV in start mode. Looks like i got a bad TTS switch. This problem all started with a starting problem and  no power to the CSV. I found a broken wire at the connector on the TTS. In the process of  repairing it the stud on the switch came loose , the Bakelite or whatever that substance is was deteriorated from age, so I bought a new switch, however I did get to repair the wire on the loose connector on the switch and I did  have power to the CSV. This coupled with your suggestion to ground the relay is telling me  the switch is my current problem.

When I get the new switch, I'll have to figure out how to bench test it before I install it.

As always , Thank you for your help.

Jim

[Bshaunessy]

TONYPENNA
  "When I get the new switch, I'll have to figure out how to bench test it before I install it."
There is a good description of bench testing the TTS in the tech manual. 
Also : elsewhere in this forum is a description of a TTS work around: adding a manual toggle switch under the dash that bypasses the entire TTS and relay circuit AND provides power to CSV when starter is engaged.  This is a handy addition , and facilitates both cold and hot starting if your TTS and relay circuit isnt quite working right.   

[BobH]

I've added a note about the manual switch to the "starting aid tour"

https://www.sl113.org/wiki/Restricted/Engine-starting-aid-tour

Details of testing the old and new style electronic TTS are on here

https://www.sl113.org/wiki/Engine/ThermoTimeSwitch

[toneypenna]

I've added a note about the manual switch to the "starting aid tour"

https://www.sl113.org/wiki/Restricted/Engine-starting-aid-tour

Details of testing the old and new style electronic TTS are on here

https://www.sl113.org/wiki/Engine/ThermoTimeSwitch

Thanks, I'll look for how to bench test the new TTS in the tech manual.
Regarding adding a manual switch, I have read about that but everything  was working before so I'm assuming once I get a good TTS switch everything should work properly again.

Thanks again,

Jim

[toneypenna]

I've added a note about the manual switch to the "starting aid tour"

https://www.sl113.org/wiki/Restricted/Engine-starting-aid-tour

Details of testing the old and new style electronic TTS are on here

https://www.sl113.org/wiki/Engine/ThermoTimeSwitch

Thanks, I must have missed the TTS switch bench  testing process when I read the tech manual, I'll have to re read it.
I saw how to test the switch when it is installed in the car which I did, that's how I determined that my new switch was defective. I have returned it and waiting for the replacement to arrive.

Jim

Thanks Again for your input.

Jim