paul325321

I have recently replaced a faulty 91161711700 thermo time switch for cold start on a 1977, 2.7 911s with an original Porsche part number 91161711701. I understand how the old thermo switch worked but do not know how to test the new unit. It doesn’t seem to respond, somewhere I saw reference that the internals are different and that wiring the unit in the vehicle should be slightly different. Any ideas ?

For interest here is a photo of the earlier unit after I took it apart -

paul325321

replaced with a new (electronic internals ?) - works great providing earth to injector for seconds while cranking then shuts off.