Dunno what this is.
I don't know what to search for, because I don't know what it is.
I need help identifying a part. It looks like some sort of check valve for the vacuum system? It's a small plastic 3 way with a very small hose going into the firewall (passenger side) by the battery. It's blue and white.

The part stumped AutoZone, O'reilly's, and Advanced Auto.

 

Those parts boys/girls behind the counter are 9 times out of 10 useless...

It's a Motorcraft YG429 Vacuum Control Valve... in short, it's for the IWE system for your 4x4.

 

Greatly appreciated, ManualF150.

 

No problem, and take care.

 

I believe even though he has a 2004, it's a Heritage, which doesn't have IWE, and I don't think he has 4wd. I believe it is a vacuum check valve for the HVAC system. The YG429 does not fit a 2004 Heritage. I think this may be what you need:

https://shop.advanceautoparts.com/fi...um-check-valve

 

Ahh, I didn't read enough into it. glc is right. Either way, good posts for someone to search on if they need to know the differences.

 

it is indeed a check valve

for the HVAC system, and the vacuum canister behind the battery box

 

It's been a long time glc. How are you?
You have pretty good memory.
Appreciate the link.

 

That was completely my fault. I could have put that VALUABLE info in my original post.
2004 F150 Heritage4.2L V6
152,005 miles
Thanks again

 

I believe it is exactly like what you think it is. It’s a check valve for the vacuum system that operates your environmental ductwork in the cab. Look up “Motorcraft YF29” and see if that looks right to you.

sorry for the years late response, the forums emailed this question to me and silly me thought it was a current question. had no idea it was from 2004 when viewing on my phone. not sure what the forums server was thinking since it looks like this question was answered years ago.

 

Nope. It's pretty current. I just have an "old truck".