tonak

Everything as far as the headlights go was just fine until I was reinstalling my driver side airduct. I managed to pull the vacuum lines off of the switch. I replaced them by braille and can still hear a vacuum leak when headlights are in the on position. I now have to manually raise them too. I swear the hoses are on the correct ports as far as function, but why the audible vacuum leak? Is that a failure mode for the switch? I love creating more work

Alan 71

Hi t,
I'm not familiar with later switches, but on the 71 switch if the hoses are reversed on the nipples the result is what you describe.
Regards,
Alan

Don Rickles

The braille was upside down? You can sneak in by pulling the lower dash panel away just enough to access the switch.

68/70Vette

Just as a whimsical aside. Installing/removing the bits and pieces behind the driver's side vertical dash board is so difficult. I just wonder how they did it on the assembly line. My best guess is that they did this with the steering column absent...my best guess is that the steering column was the last piece to be installed.

It would be really interesting to know how the factory assembled this part of the Corvette since for an individual, years later, it seems to be so difficult to work with this part of the car. For me, taking out the steering column made this part of the car so much easier (i.e. just possible) with the column out. Taking the steering column out on my 68 and 70 was really pretty simple...but a little fussy with some tedious disassembly.

Don Rickles

working this area can be frustrating! With the windshield and the upper dash pad out, it's allows for much more/easier access.

tonak

Does the audible vacuum leak make sense? I was wondering if the vacuum valve can fail and lead to the noise. I usually have the pull down switch pulled so the buckets stay up, lights on or off. The leak by itself doesn't concern me, its the tuning etc that gets screwed up. The bottom hose of the pull down switch has a light blue stripe and I attached it to the rear port on the headlight switch, it might be forced over a screw head for all I can see of it, but I'm pretty sure it's the port Rear means towards the driver, some of the sketches/videos get kind of flakey on which is which.

tonak

Latest diagram I found says..... I'm backwards, I'll reroute them tomorrow.

sullyman56

I had a similar problem with my 77. I switched the vacuum lines and it fixed it.

Dave J

There are many diagrams on the interwebs that are wrong. I always follow this rule; The vacuum source hose goes to the port closest to the pull ****. That is the port that is blocked and sealed when the valve is vented to atmosphere upon activation.

tonak

https://www.corvetteforum.com/forums...tem-works.html

These are the last diagrams I looked at, and the more I look at them, they don't match my setup from the pull down to the switch. I'll have to check tomorrow again, something isn't right. (duh)

Easy Mike

I'm am also betting the main dash harness was installed on the dash before the dash went into the car.

0Willcox Corvette

I know this diagram is correct.

You can't peal back the dash on the 1978-1982 cars, you have to pull the tach/speedo housing out of the car to gain easy access, or go from under the dash which the OP nailed it.... you're blind this way but it's possible.

Tach/speedo housing removal instructions if you decide to try it this way.
http://repairs.willcoxcorvette.com/1...-instructions/

tonak

Willcox! I think even my AIM shows the routing from pull down to switch backwards. I'm going to have nightmares about spaghetti for a few weeks now