I would disconnect wires from the turn signal switch and start over with each light, checking running light function. Make sure each one is on when parking lights are pulled on. Once that is good, run hot to the bright element in each bulb one at a time and make sure all the other lights stay on. If not, you probably have a bad ground somewhere. If that all checks out good, then re-visit the turn signal switch.



Mike
1955 Chevy 6400 ex-flatbed (no bed now!) sold September 2023
In the Stovebolt Gallery
1958 Chevy 6400 flatbed W/dump
In the Stovebolt Gallery
1959 Chevy Suburban Owned for almost 20 years, Daily Driver -- sold May 2016
In the Stovebolt Gallery

Sufficient unto the day is the evil thereof