[TR] TR250 LED tail light problem

[Brian Kemp]

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.
>>
>
> ** triumphs at autox.team.net **
>
> Donate: http://www.team.net/donate.html
> Archive: http://www.team.net/pipermail/triumphs  http://www.team.net/archive
>
> Unsubscribe/Manage: http://autox.team.net/mailman/options/triumphs/bk13@earthlink.net

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://autox.team.net/pipermail/triumphs/attachments/20191112/50bdc4b7/attachment.htm>