Topic: 47 Luggage compartment lamp


Bob-93021    -- 03-07-2019 @ 10:50 PM
  It has been awhile since I last posted. I have finally resumed working on getting my very late 47 sedan on the road. I recently discovered that it has a trunk light in it. It was not working so I removed it assuming that a wire was broken inside. I carefully took it apart and found what I think is a fuse or Mercury switch inside. Size is apx. 3/8 x 7/16. DVM across it reads open. See pix.
With a magnifying glass I can barely read “Littlefuse USA”. I have searched the green bible and 41-48 EFV8 book and cannot get any details about this luggage compartment lamp or its innards
Is this an accessory or is it standard on 47's?
Is the light on at all times when parking or headlamps are on since it is a branch of the license plate lamp on the deck lid?
Is the little tube a fuse or Mercury switch
Can anyone out there shed some light on this matter.

Thanks – Bob


len47merc    -- 03-08-2019 @ 5:05 AM
  There have been a number of posts on this subject over the years that helped me on my '47 with the original luggage compartment lamp/mercury switch. A quick search yielded this one (there are many others):

https://www.earlyfordv8.org/forum/viewmessages.cfm?Forum=18&Topic=6297&keywords=trunk%20light


Steve


len47merc    -- 03-08-2019 @ 5:08 AM
  Here is another - had to adjust my search verbiage to find one I'd posted on the same topic:

https://www.earlyfordv8.org/forum/viewmessages.cfm?Forum=18&Topic=10837&keywords=mercury


Steve


Drbrown    -- 03-08-2019 @ 8:33 AM
  Stock is a mercury switch (little bead of mercury that rolls back and forth inside to make or break the contacts for the bulb. Discontinued when mercury became illegal.

However, to fix my '47 I discovered that Cadillac (and I'm sure others) used the same device on up thru at least the 1980's on their engine and truck hoods. Not "stock" but ..... An '84 Caddy trunk lid unit I got clamped right on trunk lid frame at the lock location. You could visit a parts yard and pull one.

This message was edited by Drbrown on 3-8-19 @ 8:38 AM


Bob-93021    -- 03-08-2019 @ 9:52 PM
  Len47, Thank you for digging into past threads on this lamp. I dimly remember this was brought up in the past so I also tried to check the archives and could only go back 1 year. I read your old postings and now understand how they work. Upon disassembly I noticed the peculiar angle for the switch. If it was just a fuse it would not have need to be at an angle. My car is no where close to a Dearborn but I like to understand these things and keep to original as best possible. I might keep the original parts and just jumper the Mercury switch and have the lamp on when the parking or headlamps are on. I do not think this is a problem. At this time I will probably just shelve the part for now while looking for another Mercury switch and or move on to other things like getting the car on the road!

Drb, thanks for the insight to source a functioning light from an older Cadillac/GM that will fit. I will need to visit the local pick a part this weekend and look for something to work in the interim. A functioning trunk lite would be nice to have. Thank you all - Bob

This message was edited by Bob-93021 on 3-8-19 @ 10:08 PM


supereal    -- 03-09-2019 @ 12:27 PM
  The mercury switch trunk and under hood lights often caused problems of depleted batteries when they failed to shut off. Being in places that were not visible prevented seeing that they stayed on. As noted above, they were officially discontinued when mercury was banned. If you want to show them as optional accessories, but have them actually light, just wire them into a circuit such as taillights or parking lights that will allow them to shine, if needed.


trjford8    -- 03-09-2019 @ 5:00 PM
  I would run a hot lead to a hidden toggle switch for the light. Your wire harness should have the "hot wire" already in it for the mercury switch if the harness was made for the accessory trunk light.


Bob-93021    -- 03-09-2019 @ 10:23 PM
  Super and Trj. Thanks for ideas. I had heard of Mercury switches failing in the on or partially on and running batteries down. I just double checked the wiring and in original design the light for the luggage compartment light was a tap off the lead going to the license plate light on the trunk lid. The original design would only allow the trunk light to come on when the headlamp switch was in parking or head lamps on. I really doubt if I can source the original Mercury switch so I am thinking that I will keep the original trunk light and by-pass the Mercury switch internally. This would leave the trunk light on when head lamps are on (don't drive a lot at night) but seems like a reasonable compromise and would not require any rewiring since my car is using original harness – for now. I do plan to rewire the car sometime in the future. Thank you - Bob


39 Ken    -- 03-10-2019 @ 5:30 AM
  The "original" mercury switch will be difficult to find.
If originality is not your concern, then Google "mercury on off switch".
There appears to be many available that will do the job.


Bob-93021    -- 03-10-2019 @ 10:52 PM
  39Ken, I have given up on finding the exact Mercury switch. My car is definitely not a Dearborn car. Anyways, I will keep the original housing and bulb and for now. I will just jumper the switch so that it is on when the parking and or headlamps are on. Thank you - Bob

This message was edited by Bob-93021 on 3-10-19 @ 10:54 PM


47Monarch    -- 06-22-2019 @ 7:48 AM
  Hello I have the same light in my 47 monarch ( made in Canada ) unfortunately not working thing I'll give it another try


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