[TR] TR250 LED tail light problem
Roger Elliott
elliottr at rmi.net
Wed Nov 13 14:32:45 MST 2019
Thanks everyone,
I will do some more investigating. I should mention that the lights
just kind of flicker so it is not real obvious.
Thanks again,
Roger
On 11/13/2019 9:20 AM, David Friedlander wrote:
> Doesn't Moss sell tail light bulb holders with grounding tabs?
>
> https://mossmotors.com/bulb-holder-turn-reverse
>
> Dave
>
> image.png
>
>
>
> On Wed, Nov 13, 2019 at 12:15 AM Brian Kemp <bk13 at earthlink.net
> <mailto:bk13 at earthlink.net>> wrote:
>
> I seem to remember once upon a time, somebody made a light socket
> with a ground wire or a ground tab. I looked a few months ago for
> my GT6, but couldn't find it at the usual vendors. I imagine you
> could add a ground wire, but some of my sockets are pretty bad, so
> I was looking for new ones that already had the wire.
>
> On my TR6, I did have a socket that didn't conduct well to
> ground. The problem was the connection between the metal base and
> the metal fingers. I just hit the area with a wire brush in the
> Dremel then soldered the two bits together and it fixed that problem.
>
> Brian
>
> On 11/12/2019 2:38 PM, Roger Elliott wrote:
>>
>> I decided to give up on the issue.
>>
>> There did not seem to be much of a voltage drop across the
>> battery - about .05 volts as near as I could make out. It's
>> possible that either the meter or myself were not quick enough to
>> read accurately.
>>
>> As far as I could tell there is not a ground terminal on the
>> sockets. There was about .009 volts between the lamp housing and
>> the battery. I did run additional wires from the lamp housing to
>> a ground (to the tank mounting bolts).
>>
>> The brake/tail lights still varied with the turn signals, in
>> opposition, got brighter when the turn signals were off.
>>
>> Tested the lights with regular brake lights instead of LEDs. I
>> noticed the brake/tail lights still varied with the turn
>> signals. This is when I decided to give up and just live with it.
>>
>> Oh, the third brake light that I have wired in - power from the
>> brake lights and grounded to the body flash when ever the brake
>> lights and turn signals are on (like the brake/tail lights in
>> opposition.
>>
>> Thanks for your help.
>> Roger
>>
>> On 11/3/2019 4:37 PM, Randall wrote:
>>>
>>> Yes, that’s the idea. You want all the lights on (including
>>> turn signals) during this test.
>>>
>>> What you’re looking at is how much voltage drop there is through
>>> the ground path.
>>>
>>> -- Randall
>>>
>>> *From: *Roger Elliott <mailto:elliottr at rmi.net>
>>> *Sent: *Sunday, November 3, 2019 1:26 PM
>>> *To: *triumphs at autox.team.net <mailto:triumphs at autox.team.net>
>>> *Subject: *Re: [TR] TR250 LED tail light problem
>>>
>>> HI Randall,
>>>
>>> Thanks for the information and the tests.
>>>
>>> I just want to check something on the tests since my electrical
>>> trouble shooting ability is very limited.
>>>
>>> This section is also done with the lights on, right?:
>>>
>>> To check for grounding issues, I suggest running a wire to the
>>> negative battery terminal or negative starter cable, so you can
>>> connect the ground lead of your DMM to that. Then you can probe
>>> at the rear lights, to see how well they are actually grounded.
>>> 0.2 volt is probably acceptable, anything more than that
>>> represents a problem that could be fixed.
>>>
>>>
>>> Thanks,
>>> Roger
>>>
>>> On 11/2/19 4:07 PM, Randall wrote:
>>>
>>> There may not be a good solution, Roger. The incandescent
>>> turn signals draw a fair amount of current, which is likely
>>> more than the stock alternator can deliver (along with tail
>>> lights and so on) at idle. So it may be that the battery
>>> voltage is dropping from 13+ volts (alternator supplying all
>>> power to car) to 12.6 volts (battery supplying some of the
>>> power) and the LEDs you’re using are sensitive enough to
>>> show the difference in voltage.
>>>
>>> To check, connect a good voltmeter or DMM to the battery,
>>> then watch what it does when the tail lights and flashers
>>> are both on. If I’m right, you’ll see the battery voltage
>>> sag in time with the turn signals. The only fix would be to
>>> convert to a more modern alternator, that can keep up with
>>> the lights at idle. (I’m not certain, but I think there is
>>> a Lester unit that would look and fit the same as the stock
>>> Lucas but give more current across the board. Check with the
>>> Jaguar folks.)
>>>
>>> Another fix might be LEDs that use an active current source
>>> (so are much less sensitive to supply voltage), but I have
>>> no idea where to buy such things. I made my own using a
>>> simple 2-transistor active current limiter.
>>>
>>> To check for grounding issues, I suggest running a wire to
>>> the negative battery terminal or negative starter cable, so
>>> you can connect the ground lead of your DMM to that. Then
>>> you can probe at the rear lights, to see how well they are
>>> actually grounded. 0.2 volt is probably acceptable,
>>> anything more than that represents a problem that could be
>>> fixed.
>>>
>>> I’m not sure how the TR250 tail lights are wired. On my
>>> TR3, all the rear lamps ground only through their mounting
>>> screws, which go into clip nuts fastened to the sheet metal.
>>> Very insecure, especially if the sheet metal has a fresh
>>> coat of paint.
>>>
>>> However, each lamp has a terminal inside the housing for a
>>> ground wire. So, I made up a ground wire that daisy-chains
>>> across all the rear lamp holders, then leads around the
>>> trunk to one of the fuel tank mounting bolts.
>>>
>>> -- Randall
>>>
>>> *From: *Roger Elliott <mailto:elliottr at rmi.net>
>>> *Sent: *Friday, November 1, 2019 12:50 PM
>>> *To: *triumphs at autox.team.net <mailto:triumphs at autox.team.net>
>>> *Subject: *[TR] TR250 LED tail light problem
>>>
>>> Here's the problem. When the tail lights are on and I use
>>> the flasher,
>>>
>>> the tail/brake lights flicker with the flasher. They don't
>>> go on and
>>>
>>> off but the get brighter and dimmer. When the third brake
>>> light is
>>>
>>> hooked up it does the same thing.
>>>
>>
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