dim tailights

[artron9]

My 52 Vic has a tailight problem. During the day the lights are fine and bright. Directionals are also bright. however with a load, parking lights and or headlights on, the directionals are very weak, hardly noticable. Ive checked the grounds, replaced the flasher, put high intensity bulbs in, gloss painted the buckets, even used a flashlight reflector around the bulb to no avail. generator and regulator are fine. Charging circuit is fine. What do you think?

[19tom40]

You need at least 6.0 volts at the bulb to get the specified lumens from the bulbs. Turn on your head lights, radio and heater and then 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. Do this with and without another load. 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.

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