what is it

[bdlight4]

A friend of mine has a 2001 F250 PSD. He was asking me what the module on the passenger fenderwell is. He says it has a nipple for a vacumn line (his is missing). My rig is still in the shop till next week so I can't look at mine. Any ideas? Thanks.

[lawman349]

its an electric vacuum pump. it powers the a/c vent controller, electronic shift-on-the-fly(ESOF), and other things.

if it fails, your a/c & heat will default to defrost and if you have ESOF your 4wd will have probs engaging and disengaging.

[bdlight4]

Thanks for the reply. I'll let him know. Still waiting for my rig. I'm starting to have separation anxiety.