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TR2/3/3A LED tail lights for TR3A and positive vs. negative ground

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tomnanney

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I was thinking about buying the Moss LED tail light kit, but the instructions said that it only works with negative ground cars. My 1961 TR3A is still positive ground. Are there any reasons not to change to negative ground other than just keeping the car original? Does it really matter anymore.? If so how is it done?
thanks
tom
 
No reason (other than originality) that I know of. I've converted all the TRs I've owned to negative ground, and never regretted it.

If you don't have any aftermarket electronics, the process is simple. Disconnect the battery, swap the low tension wires at the coil and at the ammeter, reconnect the battery the other way. Repolarize the generator and you're good to go. All the other stuff (wiper, heater, starter, etc) doesn't care what polarity it gets.

Easy way to repolarize the generator is to pull off the wire from the 'F' terminal on the control box, and brush it against the 'A' terminal. You might see some small sparks, but they won't hurt anything. Then hook the wire back up to 'F' and start the engine.

But note that, if you go all LED, the turn flasher won't work correctly. You'll need to add dummy loads, or get a flasher designed for LEDs (which will have an extra wire to ground).

PS, almost forgot. If you have the original battery leads, you'll probably need to replace them. The positive and negative posts are slightly different sizes. Hasn't been an issue for me, as none of my battery cables were original.
 
In the Moss catalog, it appears that some rewiring is needed if you install LED lamps for your turn signals, but the implication is that nothing needs to be done with the tail/stop lights except take out the old lamp and install the LED lamp ... just a switch of lamps ... or am I missing something?
 
That would likely be the extent of it.

I actually found some very cheap (Hong Kong) LEDs that were so simply made that I was able to open them up and change the polarity to + ground. Possibly not worth the effort but just wanted to try some LEDs w/o changing polarity of the car or spending much dough.
 
LexTR3 said:
In the Moss catalog, it appears that some rewiring is needed if you install LED lamps for your turn signals, but the implication is that nothing needs to be done with the tail/stop lights except take out the old lamp and install the LED lamp ... just a switch of lamps ... or am I missing something?
Click to expand...
No, that's right. Assuming that you have a later car with the brake/tail combo. My TR3 has the turn signals combined with the tail lights.

FWIW, I built my own insert for the early center brake lights, which could have been either positive or negative ground. (Or even work either way, with the addition of one more part) I'll post some pictures if I can ever find the cable for my camera. Even my Lotus-driving buddy agrees that the brake light is now bright enough, even in full sunlight.
 
Here is another option: a small shop started up in the Dallas area a few years ago - the lights work great on my TR4:
https://www.litezupp.com

They can do positive or negative ground, and have a solution for the blinkers - I only used them for running/brake lights on my TR4, and have had great feedback from people impressed with how much brighter they are. NFI but I'm a happy customer.
 
My advice is also to keep the regular bulbs in the turn signals and replace the brake/park lights with the LED cluster.
You get a brighter tail light and a much brighter brake light, plus you can purchase positive or negative ground.
The LED bulbs that I tried (for signals) are bright directly in front of the bulb, but were quite dull when viewed off center.
I went with just the brake/park LEDS and like Randy I get rave reviews.
 
croz said:
The LED bulbs that I tried (for signals) are bright directly in front of the bulb, but were quite dull when viewed off center.
Click to expand...
As a side note, different LEDs have different characteristics. Many do have very narrow beams, but not all. But it's much easier to get a very bright light with a narrow beam, generally it will take a lot more power to be bright in all directions.

I used 140 degree LEDs for my brake light. Very visible to the side, but over 5 watts to get enough light.
 
Thanks for all the help. I ended up going with LiteZupp industries out of Texas. Nice product and I stayed with the positive ground!
 
tomnanney said:
I ended up going with LiteZupp industries out of Texas. Nice product and I stayed with the positive ground!
Click to expand...

Did you order the straight, or right angle LEDs? Do they seem more orange than red?
 
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