The cold start system on the '66 250SE isn't working; the valve works, the relay clicks, the system has fuel. I'm down to believing it's the thermo-time switch mounted on the firewall, but a new one is $250.00 and I don't want to buy on a guess.

How can I ensure it's the thermo-time switch?

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- Brian


1989 500SEL Euro
1966 250SE Cabriolet
1958 BMW Isetta 600