When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hello, I am new to this Forum and have just purchased a 1990 F-150 super cab 4x4 The thing is, I will be doing a lot of work on it, Suspension, New Floors etc. but I was told that it has a 1994 Engine in it.
I noticed after I bought it that the Air conditioning doesn't work, The details are that no matter what you put the vent selector to, def, floor, AC, etc. the air just blows out the Def. vents. it will blow either hot or outside temp air.
I 'm not sure where to start diagnosing this, is it possible that something was hooked up wrong or not hooked up when the engine swap was done? any help would be great.
I think you have a vacuum leak somewhere. Start lookin under the dash for vacuum lines and electric wires that are broke/craked. Then, you are probably going to have to put some more freon in you A/C, and if I'm not mistaken, if it is a '94, then you can just use R-134.
I would start at the white plastic tube under the hood if yours has it the plastic tubes break easily. The default for the system is to go to defrost if it looses vacuum. As for the A/C just start one thing at a time.(system pressure, switches etc...)
VERY possible the A/C was never hooked back up after the swap......or it was and just never vacuumed and re-charged.....It's not uncommon. For that....you should take it to an A/C place and let them check it out after you fix the vents.
Your vent selector not changing is more than likely a vacuum problem. It's all vacuum controlled.....Probly a leak as the truck wouldn't run too good if a hose was missing or not connected.
Get manuals ....Haynes and Chiltons if you can and start tracing and looking for bad vacuum hoses.....On my 92.....there is a small vacuum line on the passenger side that goes through the firewall and feeds the system.....comes off the coffee can looking thing. These are always soooo much fun to find.
Thanks, I'll check that all out today, I have a Haynes Manual so it should help. I'll be doing some other work as well while I wait for my floor pans to come in from LMC Truck. I just spent the last week sorting through the electrical. All the electrical seems to work now.
Well I checked the "Coffee Can" and it was rotted through so I removed the vent line connector and got a can cut a hole in it and epoxied the connector into it. Tried the vents again but still no luck, could it be the home made can or is it more then likely a vaccuum line?
O.k. I checked the Vacuum lines behind the glove box, the ones that go out into the engine bay, black and white, the white one goes to the vent control thing. I disconnected the lines there and checked the lines no vacuum on any of those lines.