Blend Door

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LITTELHAWK
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Location: South Kansas City

Blend Door

Post by LITTELHAWK » Sat Jul 21, 2018 2:18 am

I found the giant hole I knew had to be in my Firewall! Turns out it is the common blend door not working problem that everyone has...


I've perused the forum a bit to gather a little information but I still have a few questions. I've already checked the vacuum lines and they all seem to be connected and in good condition with no noticable leaks. I also snipped the ends off that connect to the ball to get it tighter. I still have my heater control valve, but plan to delete it when I change my heater core in a month or two.

What would be my next diagnostic steps?

I want to get it fixed but if I can't, is there any reason I couldn't just shove a bunch of plastic bags or something in the hole to prevent the frigid winter draft? (A/C doesn't work and I have very little hope or interest in paying to fix it.)
'85 Mineral Blue & '87 White Barn Find parked in '92

Ed Lijewski
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Location: The Belly of The Beast

Re: Blend Door

Post by Ed Lijewski » Sat Jul 21, 2018 7:25 am

The vacuum ball center hose connects to the solenoid valve next to it on the firewall. Check/clean electrical connection; have a helper operate the Recirc/Fresh air control while you listen for the solenoid to operate.

If OK, remove the plastic false firewall cover, and verify that the hose from the vacuum solenoid is good and connected to the vacuum motor on the side of the blower box, and that the arm from that motor is connected to the blend door arm.

YMMV
Descartes: "Cogito Ergo Sum"
Lijewski: "Sum Ergo Drive-O. Mucho!

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LITTELHAWK
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Joined: Fri Sep 12, 2014 10:54 pm
Location: South Kansas City

Re: Blend Door

Post by LITTELHAWK » Thu Jul 26, 2018 5:09 am

It seems like the vacuum motor went bad or rusted so that it doesn't work anymore. The screw head completely stripped so I used a hacksaw to cut the arm on the motor side of the screw so I can drop the door now and fix it in the future if I desire.
'85 Mineral Blue & '87 White Barn Find parked in '92

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