I scored a nice under hood light from oldspackrat (thanks Scott!), cleaned it up and had it re-plated, came up a treat.

My question is how does it turn on? I can't make any sense of the wiring diagram and I'm unclear if there is a suppose to be a switch under the hood or a door type switch somewhere under there.
I have detailed the entire engine bay and didn't come across any switch that wasn't already being used.

The car came out with the courtesy light package and the holes were in the correct place under the hood where someone had removed the original. The 2 holes even lined up perfectly with the light I was sent.

Has someone a photo of the correct setup perhaps? Thanks.

 

Underhood & trunk lights contain a small amount of mercury inside that acts as a conductor when the lamp housing is tilted at an angle (such as when the hood or trunk lid is open). Lamp is simply hooked up to a hot wire (continuously live) and the ground is achieved through the hood/trunk lid mounting. If you painted the underside of the hood, make sure there is bare metal around the bracket mtg holes. You can readily test it off the car by hooking it up to a battery and simulating the movement of the lamp as if mounted on the hood.

 

The usual connection is to a short length of black or dark brown wire (I can't recall) that comes out of the firewall connector and is hanging somewhere just under the power brake booster. This wire connects to the taillight circuit, so that the hood light only goes on if the parking lights are on.

- Eric

 

Great, thanks. I never would have worked that out. I hope I didn't ruin it when I restored it.

 

The connecting wire under the hood is brown.

 

As noted, the underhood light uses a mercury switch to activate it when the hood is raised. Keep in mind that it is powered from the parking light circuit, so it only comes on if the lights are on. This is intended to prevent the battery from draining if you leave the hood open when working on the car.

 

I'm surprised that the under hood light works only when the parking lights are on. On my '68 4-4-2, I followed the wiring diagram in the chassis service manual (it was a bit obscure and hard to understand at first) but the wire for my under hood light piggy-backs onto another connector that went directly into a hot lead. Accordingly, the parking lights on my car don't need to be on for the under hood lamp to come on. I thought I had this hooked up right because I don't remember ever having to turn on the parking lights to activate the under hood lamp and this car has been in our family since it was new (and I had my driver license)!


Randy C.

 

You're correct for 1968 (where it is powered directly from the taillight fuse), but in later years the underhood feed was connected to the headlight switch.

 

Hmmm...'73-'77 "A" bodies don't need the headlight switch activated to have the underhood light work. I've got two of them factory equipped with the lights.

 

''Keep in mind that it is powered from the parking light circuit''

I appreciate you posting this, I couldnt figure out why the hood light did not work after taking it apart a few times and cleaning the fuse box a few times...i put the parking lights on and the hood light works

 

Hmmm, my '68 the lights must be on for the underhood light to be on.

 

If I recall correctly, at least for the 70 and 71/72 A-bodies - For 1970 the hood light worked whenever the hood was opened, whether or not if the parking lights were on. The 1971 and 1972 models required the parking lights to be on for the hood light to work.


I believe this is one of the idiosyncrasies found between the three model years.