The Forward Look Network
The Forward Look Network
Search | Statistics | User Listing Forums | Chat | eBay | Calendars | Albums | Skins | Language
You are logged in as a guest. ( logon | register )

55/56 Dodge/Plymouth Dome light wiring
Jump to page : 1
Now viewing page 1 [50 messages per page]
View previous thread :: View next thread
   Forward Look Technical Discussions -> Electrical, Battery and ChargingMessage format
 
56D500boy
Posted 2018-06-08 8:22 PM (#564853)
Subject: 55/56 Dodge/Plymouth Dome light wiring



Expert

Posts: 4662
200020005001002525
Location: Lower Mainland BC
I stupidly removed my dome light many months (maybe a year) ago without marking anything wiring-wise. Now I have a NOS dome light base that I want to install and I realize that I don't quite understand how the switch works. When I had my 1955 Dodge (Plodge) the dome light was the same (I think), and I thought I could turn the dome light on at anytime with the switch (and leave it on and flatten the battery LOL). From what I understand of the wiring diagram, the switch is used to create a ground, i.e. there is 12V coming in hot to the dome light at all times, it is just when a door switch is open that a ground is completed and the light comes on. The wiring diagrams are confusing IF I thought that I could turn the switch on with the doors closed and get a light. Help an old guy and straighten me out.

Red seems to be the hot in and yellow the grounding circuit via the door switches.



Top of the page Bottom of the page
56D500boy
Posted 2018-06-08 8:42 PM (#564855 - in reply to #564853)
Subject: RE: 55/56 Dodge/Plymouth Dome light wiring



Expert

Posts: 4662
200020005001002525
Location: Lower Mainland BC
Okay. I took the old dome light base switch apart. I believe that the switch is a sliding copper bar with two "bumps" fit in detents that creates a grounding circuit between a jumper wire from the door switch ground circuit wire on the bulb socket and and the car body via the dome light base mounting screws.

I think.
Top of the page Bottom of the page
56D500boy
Posted 2018-06-08 10:34 PM (#564858 - in reply to #564855)
Subject: RE: 55/56 Dodge/Plymouth Dome light wiring



Expert

Posts: 4662
200020005001002525
Location: Lower Mainland BC
One of the reasons that I was having problems figuring out how the dome light switch works is apparently that the sliding copper bar and/or the contact points that complete the ground circuit when the switch is turned to "ON" are corroded and I wasn't getting continuity with my Ohm meter. After sliding the switch ON/OFF a few times, I got continuity and it became clear how the switch works: ON = bulb is grounded, OFF = bulb is not grounded.

While I was there, I checked continuity across the two wire connections and the bulb contacts. They are fine. (But I might clean them up a bit anyway).

Little by little.



Edited by 56D500boy 2018-06-08 10:35 PM
Top of the page Bottom of the page
lozrox58
Posted 2018-06-09 8:06 AM (#564870 - in reply to #564853)
Subject: Re: 55/56 Dodge/Plymouth Dome light wiring



Veteran

Posts: 277
100100252525
Location: Newcastle Australia
Power to the light comes from the light switch (red wire) but it is live all the time.
Ground for the light comes from the manual switch, or the door switch (yellow wire)
The dome light switch does ground thru the mounting screws. It is possible to turn the courtesy light on with the doors closed (and flatten the battery)
Top of the page Bottom of the page
56D500boy
Posted 2018-06-09 2:05 PM (#564884 - in reply to #564870)
Subject: Re: 55/56 Dodge/Plymouth Dome light wiring



Expert

Posts: 4662
200020005001002525
Location: Lower Mainland BC
lozrox58 - 2018-06-09 8:06 AM

Power to the light comes from the light switch (red wire) but it is live all the time.
Ground for the light comes from the manual switch, or the door switch (yellow wire)
The dome light switch does ground thru the mounting screws. It is possible to turn the courtesy light on with the doors closed (and flatten the battery)


Thanks. That confirms what I was thinking yesterday.

Today I remembered that I had save eBay photos of a 56 Dodge headlight switch, with wires, so I put this together (not 100% sorted, I am not good on those cloth covered wires - can't tell what they are supposed to be):



(55-56DodgeHeadlightSwitchShowingWires_Annotated_3.jpg)



Attachments
----------------
Attachments 55-56DodgeHeadlightSwitchShowingWires_Annotated_3.jpg (154KB - 68 downloads)
Top of the page Bottom of the page
56D500boy
Posted 2019-04-06 7:55 PM (#580465 - in reply to #564884)
Subject: Re: 55/56 Dodge/Plymouth Dome light wiring



Expert

Posts: 4662
200020005001002525
Location: Lower Mainland BC

While I am waiting for the last pieces of my transmission swap puzzle, I thought that I better get back to some projects that still have not been completed. The first one that came to mind was the dome light.

The original dome light that came with the car was quite rusty. I tried painting it but it look like cr@p so I searched out and found a NOS dome light (Len Dawson). However, when I got it, I tried to figure out how it worked but failed. So I took the original dome light's switch out and disassembed it. That exposed a sliding spring-loaded contact plate and a corresponding phenolic plate with receivers for the contact plate pins. The receivers were connected to a screw terminal connection for a jumper wire from the door switch ground terminal and to a jumper bar that connected the second sliding contact receiver to ground via the screw(s) that hold the dome light to the roof of the car.

I know I tried hard to figure out the NOS switch but failed even knowing how it works. That was months ago.

Yesterday, I tried again and failed. However, I did finally realize that the issue was the contact from the second sliding contact plate receiver and the bus bar that leads to the ground (via the screw that attaches the dome light to the roof). For some reason, there was no electrical path from that second contact to the ground bar.

The solution was to solder a short piece of wire from the second contact plate receiver to the frame of the dome light (very near the mounting screw as it happens). I checked the function of this system with my multimeter and also with some wire and a 9V battery. It will work finally.

Bottomline: Never assume that NOS parts are without flaws or will function without at least some tweaking.

The sketch below is not my finest hour but this issue is fairly trivial and doesn't warrant spending more time on it. (I just wanted to document it anyway)

BTW: The photos were taken with my fancy new "smart" LG Power X 3 phone. Seems to produce jpgs (not jpegs) that are easily downloaded to my desktop (via a USB cable for now).

Edited by 56D500boy 2019-04-07 12:23 PM




(55-56DodgePlymouthSedanDomeLightWiringSchematic.jpg)



(OriginalDomeLightWithSwitchDisassembled.jpg)



(NOS55-56DodgePlymouthSedanDomeLightWithRepairJumper.jpg)



Attachments
----------------
Attachments 55-56DodgePlymouthSedanDomeLightWiringSchematic.jpg (199KB - 18 downloads)
Attachments OriginalDomeLightWithSwitchDisassembled.jpg (200KB - 18 downloads)
Attachments NOS55-56DodgePlymouthSedanDomeLightWithRepairJumper.jpg (204KB - 17 downloads)
Top of the page Bottom of the page
Jump to page : 1
Now viewing page 1 [50 messages per page]
Jump to forum :
Search this forum
Printer friendly version
E-mail a link to this thread



(Delete all cookies set by this site)