Actuators are here.....driver's side:



...and here (behind glove box):



The schematic in my first post above will tell you what each of the actuators do.

 

Thank you for these. I think this is the blend door and I am thinking this is what is giving me the problem.

 

Hello I am also new to this stuff and have been looking at my vacuum lines for much time now, but still i hav'nt found out where they go I made a youtube video showing where I followed them to but don't know where the other ends go, I have 3 outta place when i bought the truck. Also i hear a hissing in the vehicle with it running so i might have a hose loose behind the glove box. But i wanted to post this on here so i could get your guys take on it. Please comment back on YouTube or on here. here is the link

THX

 

Easy stuff first...you're on the right track with the third line. With a bunch of parts moved out of the way, here is what it looks like connected:



Try using a flashlight and mechanic's mirror if you have trouble finding the nipple on the vacuum cannister. THe line you were plugging into the firewall, I believe that is the vent line coming from the transfer case. On my trucks, the line comes from the underside of the vehicle and ends right about where you were plugging it in to the firewall. I think mine actually has a clip thing that grabs onto the line and then clips into the firewall where you were plugging it in.

The line that goes under the battery tray is what powers the actuator under there, which locks the front hubs when you switch to 4WD. Don't know what happened to it that it's all chewed up like that, but it goes from the actuator to the transfer case. When the transfer case switches to 4WD, it opens a valve/switch on top of the transfer case and lets vacuum get to the actuator.

Check out some diagrams here (scroll down). Might give you an idea of where the lines should be routed to and from.

THe hissing behind the dash means the HVAC selector **** isn't sealing well with what it's connected to behind the control panel:



You can replace just that connector thing if you want (there's a part number for just that); otherwise just buy the whole control panel. But be sure those colored lines (or any other vacuum lines) are not moist with transfer case fluid. Both times I replaced the HVAC control panel (after hissing), it was because I had fluid in the lines. If you have fluid in the lines, start reading here.

Good luck!

 

Thx for the help aa21830 i think this will help me out alot, and i'll go see if i can fix it in a few if it stops raining out side, ill keep you guys posted if that works.
Thx

 

Hijacking the thread. I have a similar problem. No hot air blowing. All vents,defrost and floor actuators work properly. I can hear something happening when i switch from hot to cold air but I only get cold air and the air flow decreases out of the vents when on heat. I flushed the heater core and the inlet/outlet hoses for the core feel about the same temp so i dont think its plugged.

1998 2wd LS Blazer

 

Hey aa21830, i followed the hoses and found where u said they go. The chewed up hose, i did find it goes to the top of the transfer case to the actuator, where it was chewed up in between was a result of it getting to close to the exhaust.

The other hose from the firewall seen in the photo, i traced under the vehicle in the next photo, but i still don't see where it connects to near the firewall, and also what is the part called in the photo under the car that the hose connects to, the part has much larger hoses that goto both sides of the engine as well. I can't seem to find where it connects near the firewall, and idk if it would help me to know the part it connects with under the vehicle.

Much appreciated,
Chevyman93

 

Looks like you have one of these on your vehicle:



Commonly called an air pump. Has to do with emissions; not sure exactly what it does except pump a bunch of air out the exhaust to give the appearance of better emissions. My trucks don't have these, so I'm not sure how the hoses are routed to and from it.

 

ok, thx again aa21830 i think i can find out where the other end goes now that i know the part is an air pump, and i only have one more question for right now, could u tell me how much those hoses usually cost per ft. i need quite a bit and i'm trying to get an estimate here. & the hoses are a bit different on side for each one but that should'nt make a huge difference in price.
Thx again

 

This will give you an idea (not sure it is the right size):

Buy Dorman - Autograde 7/32 Inch x 50 Ft Vacuum Multi Purpose Tubing 506-010 at Advance Auto Parts