hello, i live in idaho and driving my beast down the highway with this vent gets very cold. its on the drivers side next to the park brake under the dash. i can close the vent but when i do the cold air comes out of the slit that the handle that shuts the vent is placed. i attached a photo below with the vent closed, the red area between the black plastic is were the cold air still gets through.

its not bad driving around town but sucks on the highways. i wanted to see if you guys knew some trick to fix this before i started getting my hands dirty. and is that vent a stock vent?

http://www.jonwaraas.com/images/tvent.jpg

thanks

edit; oh its a 79 f150 if that help

 

Yeah, it's stock for non-a/c trucks. Trucks with factory air have that vent blocked from the factory.

 

Really? Mine is a 73 with factory air (according to the VIN), and I swear that this vent is operational (and blowing cold air on my leg on the highway!)

 

The VIN won't reveal anything about having or not having AC, and I don't believe the door tag will either. If your firewall doesn't have the large cutout for the plenum, then it didn't have factory AC. That vent is blocked off with a plate and rope sealer on AC trucks.

 

oh my door tag it says "a/c" on the right hand side of were it says "int. trim" on the very bottom of the tag. Im not sure what that means, i dont have the thing that goes through the firewall so i dont have ac.

so should i just weld the vent hole up?

edit; here is a photo, sorry its crappy. u can see the a/c thing at the bottom.



and im not sure if i should post my vin online? shall i white that out from now on?

 

Sorry, I misspoke about the VIN. I have integrated a/c controls on the heater panel, the Marti report shows a/c, but I have no idea how to describe the appearance of the firewall. But I can surely say my vent works just fine. That could simply be someone else's mod though. I am still getting used to this truck!

 

LMC has the gaskets to seal that where it does not leak air. I did it on my 71 and it is sealed when closed and does not let any air leak in the winter.

http://www.lmctruck.com/icatalog/fb/full.aspx?Page=32

At the bottom.

41-1528 COWL SIDE VENT GASKET SET 1 RQ 3.95 $3.95

 

Here are some pictures of the A/C firewall (primered cab), the factory air "box" in the engine compartment (black truck) and a non-A/C cab (orange).
Tomorrow I'll take a picture of the block off plate the factory used on A/C cabs.

 

Here's the illustration from the Ford parts catalog showing the driver's side cowl vent and the block off plates.
The basic part numbers 02448 and 02109 are the block offs.
For basic p/n 02109 the parts catalog says:
Cover, cowl vent air opening
Fits 73-up F100-350 w/ integral a/c
P/N D4TZ-1002109-A
Click on the .pdf link to view
Scroll to the bottom of the page for the F series

 

thanks a ton for the info

this is the article i used to see about the a/c firewall thing ( NORTH COUNTRY SPECIALTIES ® ), i have to get my heater blowing warmer air so ill be replacing the heater motor this month sometime. its weird that my vin tag says a/c i dont have it.

thanks again for the help

 

Based on your description, and what I understand I have, I would say that this is factory a/c. Perhaps one of the POs removed the block off plate

 

Yes, that is factory air.
PS: Like the battery holddown

 

Perhaps that pic should go under the thread "Stupid Crap PO's Have Done To Your Truck?"

 

Yup, more often than not THE WORST THING that ever happens to our trucks is a previous owner.

 

Here are a couple of pictures of the factory vent block off plate.