roadster rear brake electric connection

albertaduke

former airline pilot without the big bucks
Joined
Feb 16, 2010
Messages
4,284
Location
kaleden
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2021 rocket3 GT
this question is for those who have added brake light to the rear .
before I cut and check which is which?
I see three electric line plugged into the rear light bulb, blue/ red/ and black anybody knows which one is powering the brake filament in the oem lightbulb?( bill you've done this mod)I venture to say the black is for ground so blue or red??:thumbsdown:
 
Hi Patrick, It's been a while since I did that. I "think" it is the red wire. If you have a test light, probe the feed tips where the bulb is inserted then see which it is for sure.
 
At the connector plug, the colours change from the Main Harness:
On Main Harness Yellow is Running and Green/Purple is Brake (that is absolute)
I believe the Brake would be the Blue and the Running is Red - but double-check at the connector plug to be 100%.
 
At the connector plug, the colours change from the Main Harness:
On Main Harness Yellow is Running and Green/Purple is Brake (that is absolute)
I believe the Brake would be the Blue and the Running is Red - but double-check at the connector plug to be 100%.
bill says it is the red!!and @DEcosse says it is the blue now I am way ahead thanks guys!! I guess I will follow bill's advice, I never thought of it !! I have a tester I will see what is what
I inserted and fitted (with difficulties I might add) some extra led lights inside the huge rear housing and will connect those leds to the brake line I originally was going to cut in half the housing and glue back everything but since I could stick my fingers inside that hole and being good with my fingers in small holes I gave it a go results tomorrow!!:thumbsup:
 
As I suggested, no need for meter - just look at the connector interface plug and see which colour mates up to the yellow and which to the green/purple
I identified those accurately;
not certain on the R3 but going by my Daytona convention on its tail light the running would be the red and brake blue - but if you just mate the colours at the R3 tail light connector, there will be no doubt.

Post Script - Looking at images of main harness and tail light on EBay I believe I am correct
But again, just take a quick look at the interconnect plug to validate.






i.e. when you mate the plugs in the pics above I believe the blue will mate to the Green/Purple and the Red will mate to the Yellow
Which would make the Blue the Brake wire
 
Last edited:
At the connector plug, the colours change from the Main Harness:
On Main Harness Yellow is Running and Green/Purple is Brake (that is absolute)
I believe the Brake would be the Blue and the Running is Red - but double-check at the connector plug to be 100%.

All correct
 
As I suggested, no need for meter - just look at the connector interface plug and see which colour mates up to the yellow and which to the green/purple
I identified those accurately;
not certain on the R3 but going by my Daytona convention on its tail light the running would be the red and brake blue - but if you just mate the colours at the R3 tail light connector, there will be no doubt.

Post Script - Looking at images of main harness and tail light on EBay I believe I am correct
But again, just take a quick look at the interconnect plug to validate.






i.e. when you mate the plugs in the pics above I believe the blue will mate to the Green/Purple and the Red will mate to the Yellow
Which would make the Blue the Brake wire


I put the tester to work had my wife squeeze the brake handle while holding said tester to the brake post in the housing where the bulb normally seat and the result is ....the BLUE wire carries the day
thanks for the professional help though .
had to do it that way as I am intellectually challenged when electrics are concerned ( did I say I hate working electrics)
 
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