Blinking the Third Brake Light?

[TR3driver]

Randall, I assume that the fix involves replacing the bulb holders and bulbs and rewiring to convert to signal/brake on the outside and brake only in the middle. Any advice as how to tackle this, which seems definitely worthwhile. Looks very good in the picture. Are those standard bulbs? Cheers, Mike

Nope, those are all the standard holders and the harness is still the original 1956 item. Bulbs are slightly uprated, 2357 incandescents available at any auto parts store.

I don't have a diagram to share at the moment, but what I did was to mount a pair of relays to a bracket under the dash. One side of the coil for each relay goes to the turn signal circuit for that side of the car; the other side of both coils goes to the brake light circuit. So each relay will only activate if either the brake light is on and the turn signal for that side is dark, or if the brake light is off and the turn signal for that side is on. I also had to add some power resistors to provide enough load for the turn signal flasher to work properly.

One relay contact gets fused power (I added a new fuse block near the original one), the other powers the corner bulb on that side.

Everything connects into the original harness near the LH horn.

As it happens, I wound up adding a mechanically operated brake light switch as well, because the original hydraulic one wasn't reliable. But that is not required for the conversion. My original installation had another wire that ran over to pick up the brake light circuit at the switch on the RH side, which worked fine until the switch started flaking out.

 

[TR3driver]

I'm wondering what's actually involved in converting one of these units from Neg to Pos ground ? I ordered a basic unit that does everything the other units shown here do from a company called Kapesco for under $20. unfortunatly I ordered before I knew about the Pos ground issue.

Looking at the diagram for the Backup-XP, I think a single relay would make it work for positive ground. Swap the module power leads, so black goes to the brake switch and red goes to ground; then connect the relay coil between the black lead and either white/red or red/white (for mode 1 or mode 2). Might want to add a diode across the relay coil, just for some extra insurance against the inductive kickback damaging the module. Then fused power (green circuit) to one relay contact, and the other contact to the brake light(s).

 

[mgedit]

Randall, thanks for the help with the wiring. Will refer to this when I get to the wiring part of my restoration. Cheers, Mike

 

[angelfj1]

I contacted a guy who has them on eBay and says his work for LEDs or regular incandescnet bulbs (not all do). I asked if it would work for positive ground, he replied:

"Hello, thank you for your interest! Unfortunatly, it will not. However... I can custom build you one that will. The output from the unit would then be a negative pulse rather than positive, the red wire from the unit would connect to the positive chassis and the black wire would connect to your negative switching brake light switch. The cost would be $22.00 plus the $1.70 shipping and I would need 1 week lead time. Please let me know if you are interested."

If I try this I will report the result.

Geo, I really need to add a third brake light now that I'm driving the 3A. I wanted to check with you first to determine whether or not you installed it and your opinion of the product.

Thanks,

Frank

 

[Gliderman8]

Here's what I designed and built.... It does not permanently attach to the car so it goes on and off in a few seconds.
It flashes three times rapidly, then goes to steady red.
The led by the way came off of a police motorcycle that I purchased off ebay.

 

[angelfj1]

Elliott: Thanks! That's a real nice piece of workmanship! Your car is negative earth and I was wondering if Geo was able to get the product to operate correctly in his positive earth TR3A.

Frank

 

[John_Mc]

Gliderman, when are you going to start selling kits?? That's a great design!

 

[Gliderman8]

Thanks for the kind words John... wish there was a bigger market for them.

 

[BobbyD]

I posted in the other Forum about the Moss brake light pulsar...... step on your brakes and the light flashes 3 times and then burns steady.

You can see it here

https://tr6.danielsonfamily.org/BrakeLightPulsar.htm