[rocketraider]

Do you mean as it won't open, or stays open all the time? You really need the service book to find all the components and locations.

Trace ALL your vacuum lines out and make sure none are split or unhooked. After 40 years dry rot can set in and create problems. Some of them are hidden from plain sight. A good place to start is make sure the vacuum line is connected to the intake manifold and to the vacuum tank at the left front of engine bay. If it's not connected, the vacuum system is simply not going to work.

Can you manually open the grilles?

The grille vacuum motor is behind the middle of the front bumper and not easy to get at.

Make sure the vacuum line is connected to the headlight switch, and listen for a vacuum leak hiss there with engine running. It can be disassembled and put a light coat of silicone valve lubricant in the vacuum section for a temporary fix. My 69 has been running that way for nearly 20 years. Valve lube- not RTV. Valve lube doesn't dry out.

There's a vacuum relay valve behind the left fender underhood. Also a three-port vacuum check valve that can usually be seen between the vacuum tank and fender.

Next- if it's a W34 car there is a vacuum switch in the left radiator tank that opens the grilles if engine overheats.

If all vacuum lines and connections are good, any of these components can cause headlight problems.

Do the windows work sluggishly from all switches, or just from master switch? Any switch could have some corrosion buildup on the contacts which will cause sluggish operation. You may have to pull the interior panels and clean/lubricate the tracks. If you're luck it's not bad motors- they're a PITA to replace.

I've noticed a lot of obsolete parts vendors have gotten rather pricey on Toronado electrical and vacuum parts. One in particular advertises any 68-70 part he's selling as W34 or GT, and I've called his hand on it a couple times. If it weren't for his grossly inflated prices, I wouldn't bother.