I just finally picked up an underhood light to replace the missing one on my truck. It seems most of the ones I found in the junkyard were pure junk. I bought a seemingly good one, put it in, and it does not work. I got anywhere from 2 to 10 volts between the terminals, and I can not get the bulbs to light at any voltage (they are new). Is this common? Is this worth trying to fix? How do I fix it, and does anyone know anything more about the ball bearing switch that the EPA was offering for free?
Last question is which wire should the light plug into? I can not seem to find it under the hood and I can not find it in any schematic.
It may not help you at all but I did the exact same thing, bought a junkyard light and attached it to my hood.It was a green wire with a yellow stripe that came out of the harness near the brake booster. It also helped that this wire was running along my hood already but...
Thanks, I have the strap, the wire leading to the light, and I put it into a switched source for now, because I could not find the plug next to the booster. Is there any way to clean it for the contacts, or is this a sign of the mercury switch going? Should I even try to fix it?
A toggle switch works fine. Plus they are $2 at the local ace.
A Free ballbearing switch is better that $2, and it would work as original, and wouldn't be cheezy in my opinion.
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You dont need a ground strap either. Mine is missing and my light runs fine.
Then how does your lamp complete the circut? It has to ground somewhere.
Light grounds to hood. Hood Grounds to firewall. The hood will not be grounded properly just going through the hinges. The hinges pivot and are a loose connection. It needs the Factory Ground strap.
With out removal, you may try extending the lamp several times to gain better contact between the extension and the case. Years of non-use could result in poor internal contacts that would act like a bad internal switch. I noticed with my unit though that the extending wire had been retracted in a twist next to the bulb that had become rather tight. Manipulation of the lamp in this state can cause severing of the wire internally. A volt meter used while moving the separate contact (extension, wire) may narrow the problem to the point of origin. best wishes.
Great thread! Rep for all. My '81 F250 has an underhood light that works every time. My newer vehicles have had trouble with the bulbs or did not have it at all. You guys are the best and ford rocks.
I really agree! Thank you guys for all the help...Something as menial as an underhood light has garnered a lot of response and help! I am still tinkering with this and am getting to the root of it - I hope.
I would not do the "toggle switch" mod if I were you.
The purpose for the mercury switch was to ensure that the light would only come on with the hood raised.
If you "re-engineer" it by using a toggle switch, there is a chance that you could forget to turn it off, or accidentally turn it on during the day without knowing and kill your battery.
I am always a firm believer in keeping things stock unless there is a BETTER way to do it then they did from the factory. In this case, I think the factory did it right (sans the mercury).
Used a toggle switch on my 96 XL. Worked fine. never had a problom remembering to turn out the switch. Everytime I forgot the glow under the truck gave it away.
The circuit will ground through the hinge. Try it. Please, please, dont argue worthless info.
My point still stands and I'm not "arguing worthless info".
Why would you want to "rig" something up like that when you can easily fix it so that it functions the way it should?
I personally am here to try and set an example of fixing things right, not half-baked.
Once again: the reason FORD did it like that in the first place is so that you don't forget to turn it off, and it will only turn on when the hood is up. Right when you need it.
You could easily turn the switch on during the day (either purposely or accidentally) walk away from the vehicle for a few days and kill your battery. When the mercury switch is functioning properly the light works as designed, and you NEVER have to worry about leaving it on unintentionally.
Why do you think they have automatic shutoffs on headlights these days? Don't tell me you have never left your lights on and came back to a dead vehicle.
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