Underhood lamp?

[TeamWarpath]

Anyone know how the underhood lamp is wired? I have the lamp, but no wiring. What makes it come on? I can't find it in the wiring diagrams. Is it tied to the dome light circuit?

[EricsZ28]

No. Mine ('80 Z) draws it's power form the AC power source - which is a connector on the firewall with one red wire going in and a red wire and a black wire (for the hood) coming out. This connector has a small metal bracket that mounts to the firewall. Sorry, no pic.

Light switch details: http://www.nastyz28.com/forum/showth...ht=hood+switch

[EricsZ28]

Lamp Wiring Diagram: http://www.nastyz28.com/camaro/wire/78w-acopt.jpg

On mine, the lamp hookup conects to the A/C Feed on this diagram (center):
http://www.nastyz28.com/camaro/wire/78w-eng.jpg

[TeamWarpath]

"It is a gravity switch inside the light socket. When the hood is opened, the light tilts at an angle that turns it on. When the hood it closed, the light angles so it is off."

Answers my question... I never knew about a gravity switch in the socket! Thanks!

[TeamWarpath]

I ran a wire to the lamp, and could not get it to come on. So, I took the socket apart and find that the internal contacts were very dirty/corroded. I cleaned it up, and soldered a new wire in. Here are a few pics and a video of me testing the gravity switch....


components of the lamp...


the switch taken apart, with the spring that goes around it and the c-clip that holds it into the socket...


new wire soldered to the contact...






installing the c-clip to the base....


testing with continuity test light...

[Twisted_Metal]

^ Great job on the rebuild and showing the details of the parts!

I believe it's commonly called a mercury switch.
(A drop of mercury rolls to one end and makes the electrical contact to complete the circuit.)
Of course..... mercury is bad so it's now called a "Gravity" switch.

Later GM cars have the hood light tied into the headlight circuit and it won't light unless you have the head lights on and the hood up.

[TeamWarpath]

Originally Posted by Twisted_Metal

I believe it's commonly called a mercury switch.
(A drop of mercury rolls to one end and makes the electrical contact to complete the circuit.)
Of course..... mercury is bad so it's now called a "Gravity" switch.

Yeah... I realized that after I cleaned the contacts with my tongue...

But seriously, I knew as soon as I seen the little metal 'capsule'...

[TeamWarpath]

BTW, I am using the same 50-watt 1156 bulb that is in my back-up lights... and MAN, is it bright! I can work under the hood all night and see every part of the engine compartment... like having a floodlight on the hood...