1988 CV HAVAC Question

[friskyfrankie]

Yup. access the HVAC controls from the passenger side is a bit easier than from the driver side, but you only need that if you're going all the way. Probably won't need to since you can couple the line where it's inside the firewall from the driver side. You will need to pull the controls to verify that the vacuum lines are still attached to the controls though. There's a couple of speed nuts (those press on metal disks) that hold the vacuum harness to the controls.

Will probably have to do the entire line since the "nub" of vac line, under the wiper motor, is only about 3 or 4" max and VERY brittle. Getting a line from the HVAC Control Unit through the firewall to the AC Check Valve should be the interesting part!

[gadget73]

Having done it, I promise it is very interesting. had to replace mine when I lit the car on fire after the engine swap a lot of years ago. I ran it through the original grommet, but to make that happen I had to pull the grommet into the car, drill it out to get a line through since it was basically glued/melted to the plastic, then get it back into the firewall. Not simple.

[friskyfrankie]

Having done it, I promise it is very interesting. had to replace mine when I lit the car on fire after the engine swap a lot of years ago. I ran it through the original grommet, but to make that happen I had to pull the grommet into the car, drill it out to get a line through since it was basically glued/melted to the plastic, then get it back into the firewall. Not simple.

I am already NOT looking forward to it but simply having cold air coming through the defrosters, in the extreme South is NOT cutting it! Sounds like you can access the grommet from under the dash?

[gadget73]

Kinda. I pulled the climate control head out and its basically a straight shot, but the radio and climate controls on a Lincoln are basically flipped from where they are on a Ford. You may have better access through the radio hole. I recall it being just barely accessible and it involved bleeding but I got there. Might be able to shove the grommet in from the engine bay side and shine a light through it so you can actually find the thing from the inside.

[friskyfrankie]

I like the "light" idea but I think accessing the grommet from the passenger side is nearly impossible (from under the hood, that is). Don't recall seeing it from the driver's side being any better. I'd have to be careful tying to pull the HVAC Control panel as the cable might hold it up.

[sly]

MUCH easier access on the ford/merc. You can see it right above the accelerator pedal IIRC. A little to the right of it. The vacuum line for the parking brake release is in the same grommet. When I ran a new line on the Mark VI, I just poked a new hole in one of the firewall body plugs. Was much easier that way.

[friskyfrankie]

MUCH easier access on the ford/merc. You can see it right above the accelerator pedal IIRC. A little to the right of it. The vacuum line for the parking brake release is in the same grommet. When I ran a new line on the Mark VI, I just poked a new hole in one of the firewall body plugs. Was much easier that way.

When I can get to it I will look near the acceleration pedal area and will then follow it into the HVAC Control area. Thanks for narrowing it down for me. Makes a somewhat nasty job a little easier! Since both of those lines "should" be heading off, in different directions, I should not confuse the two!

[friskyfrankie]

Got a quick chance to check it out this morning. After several rounds of colorful language, I was able to attach a new vacuum hose to the broken OEM right under the wiper motor. STILL only blowing only out of the defroster vents so still has a vacuum leak or blockage. Not sure what the alternatives are besides re plumbing the line from the check valve directly to the HVAC input under the dash. Still taking suggestions if anyone has any innovative ideas......

[sly]

Check to make sure the hoses are still attached to their points under the dash. Even if not fully seated, this could be an issue. I've had this issue with a few vehicles. While in there, verify the black line going from the firewall to the controls to make sure there are no kinks. That was the issue with the Mark VI I had that I ran a completely new line. If everything is well seated... then yeah... probably going to have to run a new source line.