I bought an old 84 Nissan Pickup last year for when it snows. There is an aut choke relay under the glove box on the passenger side that started buzzing last year. i replaced it with a new one but it buzz's also. The truck has a carb, not fuel injection. I had some problems last winter. The truck would die after driving for 15 minutes and not start for 15 minuts later. I just started using the truck this week and it has not died on me yet. Why would the relay buzz?

John

 

The oil pressure switch could be bad (sometimes it's tied into the choke) or the choke element on the carburetor could be shorted.

I would pitch both in favor of new ones (cheap enough).