Low Temperature Switch

[TJMart]

I have done some research on the 17 degree low temperature switch for my 1970 280 SL.

I have always had a slow idle when the car is first started so I tested mine and it is not working. I contacted the Classic center and it is the dreaded NLA!

Does anyone know if there is a replacement switch that will work or a source for a new one?

Thanks in advance!

Tony

[Pawel66]

I found temperature switches for my Ponton cold start system there: https://www.americanvolt.com/

I really had trouble finding parts from the usual suppliers (Delphi, Bosch etc.) knowing the on or off temperature, thread dimension, etc. It was easy to fin switches that are switching on cooling fans, for instance, but I needed normally closed switch with certain thread dimensions and had troubles with it.

[Bshaunessy]

I know my car fairly intimately (1970 280 SL,auto) but was unaware of a low temperature switch? Where, physically, is it under hood and what does it do?

[rwmastel]

Is the low temp switch = thermo time switch?

[WRe]

Hi,
the low temperature switch or 17-degree switch is part of the Emission Control System (ECS) installed in model years 1970/71 in the US.
Whereas all our vehicles have a Thermo Time Switch (TTS) which improves cold starting. See Technical Manual.
...WRe

[rwmastel]

Oh, emissions.  I was looking under starting aids.  Thanks!

[TJMart]

Bshaunessy,

As mentioned by WRe the 17 degree switch is part of the emission control system for cars built for the US.

If you car is equipped with the Emissions system, the low temperature switch works with the relays and the 2 way valve to retard the timing and in effect increases the idle until the engine warms up. It is located above the rear of the fuel injection pump threaded into the engine block.

Take a look at the technical manual  and the you tube video for a good overall explanation of the emissions system.

https://www.sl113.org/wiki/Electrical/EmissionControlSystem#Devices

Tony