Here is a site that was passed to me. I have a 90 C4, different body
than you have, but you may find some info somewhere on this site.

http://www.corvettemagazine.com/2002/february/c4lights/light1.asp

If this link works for you there is a vacuum diagram that should help
you diagnose the problem. If not just go to the base link and drill
down to the 68/82 headlight & lamps then 68/82 headlight parts &
components.
http://www.zip-products.com/Zip/dept.asp?dept%5Fid=887&gift=False&0=dept%2Easp%2
Cdept%5Fid%3D2312%26menu%5Fid%3D%26Tree%3D%2C68%2D82%20Headlights%20%26%20Lamps&
mscssid=0C68424C04014234BE367B64CB1A6EAB

If that don't work I could scan a sheet and send you a copy but that
could be very slow also.

Good luck,

They are vaccum activated and NOT many C3 owners have headligfhts that
BOTH pop right up...at the same time...

I think I gave you the C3 Registry web address so you could ask your
questions on their forums AND get the "correct" answers..plus how to
do it RIGHT .with the least agrivation...

Good luck... sorry you have Big Brrother  inspecting everything
also...

Bob G.

.

Here is the link to the guy who wrote the book that Zip and others sell.

http://www.vettevacuum.com/

Here's the guide.
http://www.vettevacuum.com/troubleshooting_guide.htm

If you email Chris, tell him your problem and if you pay for it, I bet he
can send you a PDF in email before the real one gets to you.

To get through the inspection, pull the vacuum lines off the headlights
so they just stay up all the time. If they don't, then the springs are
probably shot.

The lights can be opened manually by hand or with the vacuum switch.

I can't remember if the '80 has this or not, but earlier C3s have three
controls under the steering column.  The outside two are pull down, push up
vacuum switches.  One opens the wiper tray door (1968-1972) and the other
opens the headlights.  In '80, there may be one.  I don't have one on my '79
but I think someone has changed it.  It was included because Chevy advised
opening them and leaving them in icy winter conditions.

If that doesn't work, you can reach under the nose and push the lights up.
They have a knee-like hinge that locks into the open position.  this has to
be pulled forward to close them manually by hand.

Chevrolet in the early C3 owner's manuals advised how to do this in event of
vacuum actuation failure.  Lack of this feature does not make the car
unroadworthy, just harder to use, especially if you are in good pants.

Check for vacuum lines off.  You will find them at each headlight pod, a
vacuum switch in between the headlights under the nose panel, connected to
the front bumper torque tube (doubles as a vacuum reservoir), and then back
under the dash.  There is a check vlave at the intake manifold that looks
like a flying saucer with either one tube out top and bottom or one tube out
the top and two out the bottom.

Last is like nospam said.  Pull (and plug) the vacuum lines off the
headlight pods, then open them by hand.  They will stay open and you can
pass your test.

It's the same as the '79 I have... the lights are air operated. There
are a couple of suppliers that have lighting manuals available you can
buy that show the routing and operation of the lights.  There also is
a switch under the dash almost directly in line with the steering
wheel that 'once the lights are up' you can pull down that will 'lock'
them in place.  This was the original 'winter driving' setting..
There a pneumatic operators positioned for each light, as long as they
are not failed, the lights should stay in place to get you through
inspection.

Suggest that you invest in a "Mity-Vac" tool and the headlight vacuum
hose schematic so you can troubleshoot the components in the system.  On
my '74, one H/L actuator and both vacuum relays were bad.  Relays can be
fixed by disassembly and greasing the spools with white grease.  Also
check the front tubular frame crossmember for rust holes or collision
damage as it is the vacuum reservoir for the system.

As suggested by another, you can raise them by hand for the time being to
get the car plated.  Have fun.

Bill