Topic: rear brake & turn signal lights


dggohl    -- 05-12-2018 @ 6:49 AM
  I have a 1952 Mainline. I finally got the wiring correct for the running lights, turn signals and brake lights. The front blinkers work fine, bright and blink as normal. The rear do blink, but so dim can see them. Same with brake light. Any suggestions?


pauls39coupe    -- 05-12-2018 @ 7:09 AM
  I would check the grounds. Too much paint can insulate the light housings from the body causing dim lights.


cliftford    -- 05-12-2018 @ 7:18 AM
  Check tail lights. If you have bad grounds, they will be dim also.


trjford8    -- 05-12-2018 @ 7:24 AM
  Make sure the light housings have a good clean ground. If necessary you may have to run an extra wire from the housing mounting stud to a good clean ground on the body or frame. You symptoms definitely are a grounding problem.


TomO    -- 05-12-2018 @ 10:49 AM
  You need at least 6.0 volts at the bulb to get the specified lumens from the bulbs. Raise the engine rpm to 1,000 1,200 and measure the voltage at the BAT terminal of the voltage regulator. It should be at least 7.0 Volts and not more than 7.5 volts. If it is outside of that range, your charging system is not adequate and needs servicing.

If it passes the test, check the voltage at the back of the brake light bulbs with the brake light switch shorted by a jumper wire. You can use a small paper clip to slip inside the bullet connector to see what the voltage is. I suspect that the voltage will be low. Try to isolate the problem by measuring the voltage at the brake light switch and the turn signal switch and flasher. Use your wiring diagram to find the voltage path from the battery through the switches to the lights.

Tom


carcrazy    -- 05-12-2018 @ 11:12 AM
  It is possible that the tail/brake light bulbs are wired up backwards where the brighter filament is being used for the tail lights and the dimmer filament is being used for the brake/turn lights. You can switch the wires at the bullet connectors closest to the tail lights to see if this is the problem.


40cpe    -- 05-12-2018 @ 11:15 AM
  It's a wild guess, but you said you have been working on the wiring: Are you sure the running lights are powering the low side of the bulb, and the brake/signal wire is powering the bright side?


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