Parking light ?

I have a 71 Demon, the parking light bulbs are really dim. You can barely tell it is lit with the lens off. The signals work fine. I changed the bulbs and that didn't fix the problem and it seems to be grounded good. The horn doesn't work either and they come of the same harness. thanks for your help

Use a voltmeter and measure the voltage..
Sounds like it is on low side...

Just my $0.05....

With the lens off run a jumper from the batt neg post & touch the edge of the brass bulb case with it in the socket & lit up, with a thin needle probe to see if it is a ground side or power side resistance problem. Ground side issues are more common but you said the large filament ts/brake lights work fine. It can feed back thru the other filament but post what you get

I agree with RR sounds like a ground problem.Rocky