MinnesotaJeff

I've been searching all morning....... I have a vacuum diagram but can't locate the small, hard black line that is supposed to go through the firewall and feed the control switch behind the glovebox on '79. I found the grommet that passes through the firewall, and two of the three lines are there and in good shape, but ont he engine side the black supply line is missing. I've searched and searched and can't find any remnants of it, nor can i find the tee that it is supposed to originate from. Any help?? I've followed every vacuum line i can find and am coming up with nothing. Can i buy some of this small hard line at a parts store and just splice it into a line to get the vacuum supply for this switch?

Easy Mike

It might have a white stripe on it. Here's 81; 79 is probably similar.

MinnesotaJeff

Thanks Mike, yea I have that diagram. It's the "source" line on the engine side that I just can't locate anywhere. Pretty frustrating.

78IndyPace

If the "T" fitting is gone and you can't locate the small black vacuum supply hose, I would guess a previous owner removed it.

Here's a link to a heater/AC vacuum system diagram for a '77 Vette that also applies to my '78 - and likely to your '79. It's been a big help to me over the years:

Peterbuilt

The 'source' line starts at a fitting in the intake manifold just behind the carb.

MinnesotaJeff

Well, i created a new source line and go ti all hooked up. Now my brand new Bypass Vacuum switch that sits behind the glove box doesn't seem to work. I can compress it through it's full travel and it's still sending vacuum to the heater control valve all the time. The bypass switch is brand new. Great... guess i need to order another one?? I press it slowly with my thumb and I have a vacuum guage hooked up to the line that goes tot he heater valve. Steady vacuum the whole time.

hunt4cleanair

Nice!

mdshec

Could you email that to me?

NewbVetteGuy

Right-click on the image "Save".

NewbVetteGuy

MinnesotaJeff, out of curiosity, what problem are you trying to solve?


Adam

NewbVetteGuy

I have a 79 with the engine out right and can get you a clear picture of the "T" and original routing, if that's at all helpful.

Adam

speedreed8

You realize this was 8 yrs ago 2012 !

NewbVetteGuy

nope. Didn't realize.

I had one set of tabs open from search criteria and one open from new posts and confused the two, apparently..

Adam