99 EB, 5.4 heater box

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tekrsq

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Can anybody tell me exactly how many motors and doors are installed in the heater box for the 1st gen Expy's ? A few years ago, I replaced the blend door, and actuator along with the heater core because I wasn't getting any heat heat from the front, and most of the air was just about always being pushed out the defroster vents. Anyway, dropped the dash, replaced the heater core, blend door, and actuator. All was fine until last winter. I noticed my heat wasn't getting as hot, and the air was not coming from the specific vents I wanted. I've been told there are AT LEAST 3 sets of actuators and doors (depending on the function wanted). What the hell are they called ? I don't want to keep doing this crap every couple of years, so I want to replace EVERYTHING in that heater box that either moves, or makes something move.......in hopes I will not have to screw with it for many years to come. I know somebody cab help me out.
 

rjrodney

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I think all the other vents are controlled by vacuum lines. Did you maybe disconnect one while you were working on your blend door? I think they are just called registers.
 
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tekrsq

tekrsq

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I think all the other vents are controlled by vacuum lines. Did you maybe disconnect one while you were working on your blend door? I think they are just called registers.
I don't think I pulled anything lose. It worked fine for a few years.....then it didn't. I'm not happy about pulling the dash again, but I will in order to fix this. BUT, this time, everything will be replaced so hopefully it'll stay fixed for a while. I just need to know exactly what to order. All I can find is the blend door and actuator, but I know there is at least 1 other setup for the "mode" doors (which I'm pretty sure is my issue)...and some people claim there are a total of 3.
 

rjrodney

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Don’t need to pull the dash anymore if you did the blend door and heater core. Start with the defrost actuator.
Thread 'AC stuck on defrost'
https://www.expeditionforum.com/threads/ac-stuck-on-defrost.39532/

It sounds to me like you need to invest in ALLDATA.com. If you plan to spend a bunch of time and parts spend a little money and save yourself some headaches. I just re-upped our truck subscription and signed up my little Toyota too. Just the wiring diagrams are worth it to me.
 
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tekrsq

tekrsq

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Don’t need to pull the dash anymore if you did the blend door and heater core. Start with the defrost actuator.
Thread 'AC stuck on defrost'
https://www.expeditionforum.com/threads/ac-stuck-on-defrost.39532/

It sounds to me like you need to invest in ALLDATA.com. If you plan to spend a bunch of time and parts spend a little money and save yourself some headaches. I just re-upped our truck subscription and signed up my little Toyota too. Just the wiring diagrams are worth it to me.
ALLDATA.com is waaaaay out of my price range. I'm not a shop, lol. How in the world do you access the defrost actuator and/or mode door without pulling the dash ? Most of the vacuum lines and check valve has been replaced. However, the main vacuum line running through the firewall near the ECM has not. It seems VERY attached to whatever it connects to under the dash. I was afraid to pull it off, because I wasn't sure I could get the new one back on.
 
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