I am looking at my dads truck for a project and started it after 12 years of sitting run good for a day. Next day went out to the truck really cold morning would not start turned on the head light and a relay started buzzing inside where the fuze panel is. Took that one out and the next one did and so on. Got the relay to stop buzzing for just a second and the light come on and it almost started but started buzzing again don't know where to start but any help would be nice also will not be able to tell you if it helped as I go to school in wyoming and my dad lives in oklahoma. I will be home in december though.

 

I would put a multi-meter on the battery, and find out if you have a good voltage. If the voltage is good at the battery, check the voltage at the relay. Under-voltage can cause a relay to buzz.

Hope this helps.

Viking Panels