I recently had my dash apart to change the tach board and headlight

switch. I couln't open the headlight doors with the switch, I had to use the overide switch. After installing the switch I've had numerous

problems. at first the lights operated ok, but then they stopped working and I can hear air leaking from the switch, and I'm getting a

loud noise like a whining sound from the vacuum canister. I called ecklers who I ordered the switch from. they said they had a batch of defective switches and sent me a new one. I installed the new one but still have the same problem.  Also anyone know what causing the loud noise which I also get when I turn the ignition key on to accessory.

its definitely not alarm for the key, the noise seems to be coming from the vacuum canister under the hood,it sounds like a groan and when engine is running its a whining sound

I would pinch the vacuum lines to the headlight switch and see if the noise quits.  You may have another bad switch.

Could be the actuator(switch) valves, too. They are up under the front, between the actuators(the big, round cans). Did it make this noise before?

It all started after removing dash and replacing headlight switch.

I may have loosened another vacuum line, or have another bad switch. are there any other vacuum relays close to the vacuum canister.

If this "noise" only started after you changed the light switch, then the source has to be in the vac. lines in the cabin. You didn't do anything under the hood/front of the car, so it doesn't make any sense that the source is up there. That's just where the result is. Double-check the routing of the vac. lines to & from the lightswitch. You may now be routing vac. to a diff. place up front than it shoud be.

Also, I have seen some vac. canisters develop a crack in them that will "whistle/wheeze/vibrate" when they get to a certain amount of vac. Might be worth checking the canister with a vac. pump to test the integrity of it. The new light switch may be allowing the system to hold enough vac. to make the canister "buzz", where it did not before, or opened up a crack that was just barely holding with the old switch on it. Hope this makes sense.