toddbrett

I am planning to do a new wire harness installation on my 1977 F150 and have started to create a wiring diagram for what is in place today. I am not sure what the function though is of this ball shaped object in my engine compartment. I had thought it was initially the horn but I do not see any electrical wires running to it. I appreciate any feedback.

techrep

iTrader: (1)

Looks like a vacuum diaphragm.. the other ends goes too ? Brake booster ?

tyoder59

Vacuum canister. Used on most cars to keep climate control operating properly on acceleration. No vacuum equals default to defrost.

toddbrett

It runs through the firewall behind the brake booster. I have not yet pulled the dash apart enough to trace where it is connected.

techrep

iTrader: (1)

Tyoder is probably correct if it runs through the fire wall.

toddbrett

Thanks guys! I appreciate it.

techrep

iTrader: (1)

You bet. That engine bay looks really clean for a 77

toddbrett

Thanks, someone before me did an ok job of cleaning and painting it. I just bought it a couple months ago. They likely painted the engine bay the same time they painted the body green. From what I can tell from inside the door panels and dash the truck was originally red.

F150_1138

Had one on my 78 Ranchero that looked like a tin can painted black. It too had a single vacuum line going to it.