Results 1 to 6 of 6

Thread: License plate lamp

Discussions of Triumph motor cars

  1. #1
    Obi Wan
    Join Date
    Dec 2005
    Location
    Washington State, USA
    Posts
    2,037
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    License plate lamp

    Got a problem I donít understand with my license plate lamp. The license plate lamps do not come on. I tried using a test light. I grounded the tester to the body. When I touch anywhere on the lamp base, the light comes on. I would think that the tester should only come on when I touch the small metal button at the bottom of the socket. Any ideas on how to correct this? I have not had this car long, and have no idea what the PO has done. Any ideas are appreciated.
    Kevin

  2. #2
    Great Pumpkin NutmegCT's Avatar
    Join Date
    Jul 2004
    Location
    Connecticut USA
    Posts
    11,724
    Blog Entries
    1
    Thanks Thanks Given 
    102
    Thanks Thanks Received 
    128
    Thanked in
    119 Posts

    Re: License plate lamp

    Kevin - Remove the license plate lamp bulbs. Ground the test light to the car's body. Now touch the test light to the part of the bulb socket that carries the voltage. Does the test light go on?

    You need to check that proper voltage is there, and where the voltage is going - with the bulbs out of the loop.

    Tom M.
    Last edited by NutmegCT; 05-18-2020 at 10:18 AM.
    Mac & Phyllis Take a Trip: http://nutmegflyer.com/trip-details-daily-updates/
    History: 1976 MGB, 1959 Triumph TR3A, 1960 Mercedes-Benz 190b, 1958 Rambler American.
    Current: 1953 MG TD27318.

  3. #3
    Obi Wan
    Join Date
    Dec 2005
    Location
    Washington State, USA
    Posts
    2,037
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    Re: License plate lamp

    Thanks for the reply. I did take the bulbs out. The little knob at the bottom that touches the bottom of the bulb lights up the tester when I touch it. The odd thing to me is if I touch the lamp base anywhere with the test light, the tester lights up. I pulled the wires out, and it looks like the PO cut the two red wires and then twisted them back instead of unplugging it. I taped them for now to make sure they were not the problem. How do these bulbs get grounded? I still do not understand why there is voltage going to the entire base.

  4. #4
    Great Pumpkin NutmegCT's Avatar
    Join Date
    Jul 2004
    Location
    Connecticut USA
    Posts
    11,724
    Blog Entries
    1
    Thanks Thanks Given 
    102
    Thanks Thanks Received 
    128
    Thanked in
    119 Posts

    Re: License plate lamp

    Kevin - is the lamp unit this one:

    TRS-075_1.jpg

    If there's power going to the entire frame of the unit, then you need to trace what wire is supplying the voltage to it. Wire supplying current should only be connected to the bottom of each "cylinder socket".

    The ground for the bulbs is the entire lamp unit, which is bolted onto the frame of the car. Some guys add a separate wire to the unit, to provide a more stable ground. If there's an extra ground wire, maybe it's somehow connected to a voltage source. That's not good.

    Tom M.
    Mac & Phyllis Take a Trip: http://nutmegflyer.com/trip-details-daily-updates/
    History: 1976 MGB, 1959 Triumph TR3A, 1960 Mercedes-Benz 190b, 1958 Rambler American.
    Current: 1953 MG TD27318.

  5. #5
    Jedi Warrior Rhodyspit75's Avatar
    Join Date
    Dec 2009
    Location
    Cumberland. RI
    Posts
    767
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    10
    Thanked in
    10 Posts

    Re: License plate lamp

    Yes remove the bulbs and test. It’s most likely lack of ground. If the bulbs are in when the test light lights it’s because the voltage is traveling through the filament.
    "Age considers; youth ventures." Rabindranth Tagore
    1975 Spitfire

  6. #6
    Great Pumpkin NutmegCT's Avatar
    Join Date
    Jul 2004
    Location
    Connecticut USA
    Posts
    11,724
    Blog Entries
    1
    Thanks Thanks Given 
    102
    Thanks Thanks Received 
    128
    Thanked in
    119 Posts

    Re: License plate lamp

    Kevin - any progress?
    Mac & Phyllis Take a Trip: http://nutmegflyer.com/trip-details-daily-updates/
    History: 1976 MGB, 1959 Triumph TR3A, 1960 Mercedes-Benz 190b, 1958 Rambler American.
    Current: 1953 MG TD27318.

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •