'41 ford trunk compartment light

[fordor41]

So I'm in my trunk ('41 S/D Fordor) and noticed the trunk compartment light and decided after 22 yrs to get it operating. Wire was there but never hooked up. I replaced the cloth covered wire and reinstalled. Then wondered how to power it up. Got the wire diagram out and see it's powered by the tail light circuit. So I have to have the parking lights on to power the light. Then I see there is a "compartment switch" in series with the switch on the diagram. Anyone know where/ what this mysterious switch is?

[V12Bill]

If there were no switch, your compartment light would be on when ever the parking light was on. The Lincolns worked the same way.

[cmbrucew]

I believe what you need is a mercury switch. Lid closed, light off, lid open, light on.
I did not use one on my coupe.
Bruce

[adileo]

Does the Mercury switch also need parking lights on to work? I have a 39 and a Mercury switch but never thought to turn on parking lights.

[JSeery]

The trunk light is wired in with the tail lights, so it would be on whenever the tail lights are on, parking or run. The switch is to turn the light off when the trunk is closed and the tail lights are on.

[Marvin/TN]

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Yep, mine has a Mercury Sw and I think my under hood light works the same way.

[adileo]

Thanks just took mine out of trunk wire direct to battery (all angles) light won't come on my guess Mercury switch bad.

Sorry fodor41 I hijacked thread. Think you also got your response.

[Old Henry]

Here's a light with mercury switch that will work if you can't find an original style: http://www.macsautoparts.com/store/h...unk-light.html

[fordor41]

Originally Posted by JSeery

The trunk light is wired in with the tail lights, so it would be on whenever the tail lights are on, parking or run. The switch is to turn the light off when the trunk is closed and the tail lights are on.

I understand this but where is this switch that is on the wiring diagram?

[fordor41]

Originally Posted by Old Henry

Here's the light with mercury switch: http://www.macsautoparts.com/store/h...unk-light.html

My light is nothing like that. The socket is mounted to a metal bracket that fits up into the drivers side trunk hinge. No mercury switch.The socket ends up about at the pivot point of the hinge.

[JSeery]

Originally Posted by fordor41

I understand this but where is this switch that is on the wiring diagram?

The wiring diagrams indicates it's in the switch, it doesn't illustrate a separate switch. If it's automatic it would be a mercury switch, if manual, it would be a switch built into the light bracket.

[fordor41]

Originally Posted by JSeery

The wiring diagrams indicates it's in the switch, it doesn't illustrate a separate switch. If it's automatic it would be a mercury switch, if manual, it would be a switch built into the light bracket.

No switch on the bracket, just the socket with a wire. Bracket looks like a factory piece, fits exactly into the curve of the hinge

[JSeery]

Originally Posted by fordor41

No switch on the bracket, just the socket with a wire. Bracket looks like a factory piece, fits exactly into the curve of the hinge

I wouldn't like that arrangement, the light in the trunk would be on any time the tail lights were on. It also does not match the wiring diagram which clearly states, truck light & switch. Maybe someone will have a photo of one installed (original).

[Graeme / New Zealand]

Originally Posted by fordor41

My light is nothing like that. The socket is mounted to a metal bracket that fits up into the drivers side trunk hinge. No mercury switch.The socket ends up about at the pivot point of the hinge.

Same here on my 48.

GB

[JSeery]

The 46 - 48 wiring diagram also shows a trunk light/switch but is wired a little different, it is connected in with the dash lights and license plate light.

[Old Henry]

This is the original trunk light fixture that was in my 47 until the mercury switch quit working. The mercury switch is in the light fixture. When I could not find one exactly like it I replaced it with the style Mac's sells that I referred to earlier.





Here it is disassembled showing the mercury switch inside.

[JSeery]

Henry, that looks a lot more like what I would expect it to look like!

[adileo]

That's the one I had in my 39.

[Old Henry]

Here the fixture is disassembled showing the mercury switch inside.

[adileo]

Is there a way to use (the org casing) it without Mercury switch and and splice in a inline switch?

[JSeery]

Sure, just wire it up that way. Just need to remember to turn it off!

[adileo]

Originally Posted by JSeery

Sure, just wire it up that way. Just need to remember to turn it off!

Thanks JS. I was thinking if you remove the Mercury there would be a void that would need to be filled some how. I'll take mine apart and see what I can come up with. Will share if I get to work. Ideally I'd like to hook/connect to dome light

[supereal]

The switch is inside the socket, and is a mercury (liquid metal) type, not to be confused with the car brand. The accessory under hood light is the same type. In many cases, the switch part has failed long ago Most just connect in the license plate lamp lead inside the trunk lid. The idea was to come on when the trunk lid or hood was opened. This could lead to a "parasitic" draw if the light stayed on, and many were connected directly to the license light wire so it would come on only when the lights were used. This accessory was probably devised to allow the dealer to get a bit more money when the postwar cars came out.

[JSeery]

Originally Posted by adileo

Thanks JS. I was thinking if you remove the Mercury there would be a void that would need to be filled some how. I'll take mine apart and see what I can come up with. Will share if I get to work. Ideally I'd like to hook/connect to dome light

Need to replace some of the internal parts with a spring to connect between the rear where the wire comes in the the S shaped contact on the bulb end. You will also need to place a plastic sleeve around the outside of the spring so that it can't come into contact with the case. Let me know if you want me to draw you up a diagram.

Connecting to a different light source requires re-wiring. You have to run a wire from the one doing into the light switch/socket to the wanted power source.

[Old Henry]

Originally Posted by Old Henry

Here the fixture is disassembled showing the mercury switch inside.

You can see that the mercury switch is like a glass fuse. Just wrap it in tin foil and reinstall and the circuit will be complete.

[supereal]

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To use the original lamp sock, pry it open and replace the mercury switch (the little cylinder) with a spacer, or solder the wire directly to the socket. If you run the lamp using the license plate feed, you will eliminate the problem of forgetting it with an inline switch.

[JSeery]

Both good ideas, lots of ways to get there. The stock wiring is the tail lights and/or license plate light feed, so your ok there. That's what I would use. Starting in 46 it was wired into the dash lights, I don't see any advantage to that.

[adileo]

Yup can go either way. I like dome light for two reasons.

1) tail lights or plate light means trunk light is on whenever your driving at night
2) dome light you will see on and it will help us seniors to remember trunk is on too

[JSeery]

Originally Posted by adileo

Yup can go either way. I like dome light for two reasons.

1) tail lights or plate light means trunk light is on whenever your driving at night
2) dome light you will see on and it will help us seniors to remember trunk is on too

What I intended to say is I would use the tail/plate wire with a separate switch to turn the trunk light on and off (when the tail lights were on). If I was doing it and wanted to keep the look of the original lamp socket, I would find a mercury type of switch and place it out of sight so that it turned on when you opened the lid. A lot of different ways to accomplish that as well.

[adileo]

I took the stock switch apart. Added in a metal spacer to fill the void of the mecury switch I removed. Tried it direct to battery it works.

While I like the dome light idea. I can't find a way to wire it in after the switch and to the trunk. My plan now is to run a new wire (unless someone has a better idea) from dash to trunk light with an inline switch under dash.

[JSeery]

Originally Posted by adileo

I took the stock switch apart. Added in a metal spacer to fill the void of the mecury switch I removed. Tried it direct to battery it works.

While I like the dome light idea. I can't find a way to wire it in after the switch and to the trunk. My plan now is to run a new wire (unless someone has a better idea) from dash to trunk light with an inline switch under dash.

That'll work, an added feature, if you want to go to the trouble, would be to put an LED indicator light in with the switch so you know when it's on.

[fordor41]

Originally Posted by Old Henry

This is the original trunk light fixture that was in my 47 until the mercury switch quit working. The mercury switch is in the light fixture. When I could not find one exactly like it I replaced it with the style Mac's sells that I referred to earlier.





Here it is disassembled showing the mercury switch inside.

Mine looks exactly like yours except instead of a mercury switch inside it has a fiber square with a contact/wire,a coil spring and another fiber square, 2 piece split block at the end that is held in place with the 3 bent tabs. Also no insulator and no square with the S shaped contact .

[adileo]

Originally Posted by JSeery

That'll work, an added feature, if you want to go to the trouble, would be to put an LED indicator light in with the switch so you know when it's on.

I like that idea. I went online and all I could find was 12v Led. Do they sell 6 volt Led switches?

[fordor41]

Ok, figured it out. 20 yrs ago I disassembled the trunk light because it didn't operate. I "thought" the mercury switch was a fuse and was no good, as I checked it with a meter,so I reassembled the parts to make the bulb light. Dummy me I should have tipped it to operate the switch. I believe it's still in my garage somewhere and will try it again. Like the idea of powering with the interior lights. Thanks guys

[Old Henry]

Originally Posted by adileo

I like that idea. I went online and all I could find was 12v Led. Do they sell 6 volt Led switches?

Rather than trying to incorporate the LED light in the switch, the switch could be hidden under the dash and a separate small LED mounted under the dash to show.

This is my electric backup fuel pump switch on the left that lights the red LED and the fog light switch that lights the yellow LED.



From the driving position you don't see the switch, just the light. The green LED right of the steering column reminds me to turn off the kill switch relay when I turn the engine off.





LED is from Radio Shack. https://www.radioshack.com/products/...ant=5717557253 They're called 12 volt but work with 6 volts.



So is the switch. https://www.radioshack.com/products/...ant=5717516293



The small LED lights can be stuck anywhere you want with this:



Don't laugh. It works. It is hardly visible and never comes loose nor falls down, unless you want to relocate it like I did the pump light from the second picture to the first one when I added the fog light LED. Then it's easily detached and moved.

[Old Henry]

Originally Posted by fordor41

Ok, figured it out. 20 yrs ago I disassembled the trunk light because it didn't operate. I "thought" the mercury switch was a fuse and was no good, as I checked it with a meter,so I reassembled the parts to make the bulb light. Dummy me I should have tipped it to operate the switch. I believe it's still in my garage somewhere and will try it again. Like the idea of powering with the interior lights. Thanks guys

You can easily resurrect the tilt switch by adding one of the many mini mercury tilt switches available. https://www.google.com/#q=mercury+switch They won't fit inside of the original fixture but could be attached to it with circuit going through it from the license plate light wire as original. Then, when you want the trunk light on, you just pull the headlight switch to either park or headlights and open the trunk. That's what I do and how it was designed to work. Way easier than running some separate power wire from the front of the car to the trunk light.

[47Monarch]

I have a Mercury switch in my 47 monarch not working but yes lights have to be on my

[drolston]

I carry a battery powered LED lamp with a magnetic base in the spare parts box in the trunk. Pop it on when needed in the trunk or anywhere else. Easier and more effective than running wire and jury rigged switch.

[4dFord/SC]

Originally Posted by adileo

Is there a way to use (the org casing) it without Mercury switch and and splice in a inline switch?

Replace the mercury switch with a short piece of copper wire or other conductor, like a small metal spring.

[Bob-93021]

My trunk light in my 47 sedan was not working. From the wiring diagram I see that it gets it power from the tail lamp circuit. I found the Mercury switch was defective. I would like to rebuild the stock unit if possible. Later model Fords and GM used a similar Mercury switch. I have one from a 1997. It has a similar cylinder in it. I think that this could be re-used in our original bracket. Another project that is on my to do list. I have never posted pix here but will give it a try. (hope it works) - Bob