Anyone have any idea what this MIGHT be?
2004 e350 super duty originally used as airport shuttle bus


bonus question: why is my bus only turning on when connected to another car through jump cables? I just replaced the battery and I replaced the modified vehicle power fuse that busted. Bus is still dead second it’s powered off. No dash lights, nothing.

 

Is there only one battery? Our standard passenger van has a factory second battery in the frame behind the front passenger seat.

Interesting cylinder. Looks like the small wires go to the relay on the firewall. Is that a cable or fluid line going out towards the driver side? Actually, it looks like the idle air valve in a Porsche 993. Yeah, not helpful.

Does you bus run on gasoline or CNG?

Sixto
07 E350 5.4 195K miles

 

Ahh just figured it out. It's a high idle device!