hello all, first post here.

so my brother in law comes over on Monday and says "hey, you want my old truck?" (he recently for a newer truck and has been trying to sell his 92 4x2 flareside) I have been wanting a truck but haven't had the money, so I say sure, I'll take it off his hands.

The pros: it's free, is pretty well loaded with options, and only has 90k miles on it.

The cons: it's pink (probably has so few miles because nobody wanted to be seen driving it), and while it's running well now, he's gone through a few fuel filters, making him think the tanks might need to be cleaned out... it's running fine for me though, so I'll reserve judgement on that one.

anyway, on to the problem. I was checking out what worked and what didn't on it, and while the AC seems to work, it is only blowing out the defroster vent. before I start tearing into the dash, maybe someone who has dealt with their vent/AC system could tell me what I might look for... (or if I'm missing some dash vent lever that I haven't noticed)

thanks.

 

under the hood by the heater box is a white hard line, it is real small. thet is prolly broke. thats where i would check first.

but under the dash there are about 6-7 colored lines on the pass side. all those control the climate control system. and tthey are know for taking a dump and causing air flow problems.

 

I would go with the white tube at the heater box also it's a common problem with our trucks

 

Had that problem so I went to autozone and bought a new vac line

 

Awesome, I went out to investigate, and the white line was in tact. the valve (does anyone know the proper term for it in case I need to replace it?) sounded pretty chunky, and was not moving for any of the climate setting, so I wedged it open, but the vents still didn't work. (in fact I still have no idea what that valve does... by the placement right on the blower, maybe it's the for fresh/recirculated air?)

but that lead me to the valve under the dash, with the blue line running to it. manually actuating that valve opened the dash vents, so now it is just a question of tracking down the problem. I gotta get to work today, so it'll have to wait, but now that I know where to look, I can track it down.

 

Climate control vacuum valve, I've also heard them called vacuum motors and vacuum dashpots.
Good deal sounds like you're on the right track all of it is controled by the main control valve on the dash. So now you have to see if the valve is getting vacuum or why not.

 

That's for the outside air vent, nothing to do with where the air comes out. There's another hard vacuum line that goes through the firewall that supplies vacuum to the dash vent controls.

 

Update:

turned out to be a piece of cake. I went out this morning and crawled in to look under the dash, loosened the climate control panel, and then thought maybe I should start at the source of vacuum. so I open up the hood and start tracing the tubes. I went from the T joint in the attached photo an found the perpendicular tube to be dangling. I look around and see the vaccum source on top of the manifold with one port capped... so I uncap it, confirm it has vacuum, and slide the tube on. then "POOF!" everything works.

I am wondering though... is that where the climate control is supposed to hook up? and if so, why might someone intentionally disconnect it? it seems they must have done it on purpose since it was capped.

anyway... for now, the truck is still running, and the climate controls work.

 

It can hook there, but may have come disconnected from a line already connected there. Just make sure there is no vacuum leak and it's fine.