Customs Turn Signals

Gentlemen,
I have wired my 1939 Deluxe turn signal switch (allstate 8141) to my car. All lights work. The issue I have is when I turn on my running lights I loose the turn signals. The flasher clicks once and that is it. I am running stock tail lights and ad on fronts that are not LED. I am using a 12 volt Negative ground. I have made my own harness. Any suggestions will be welcome.
Thanks,
Wick

 

Do you have twin filament bulbs in those lights?

 

Take a deep breath, relax, start over.

 

Did you make sure that the turn signals use the "bright" filament at every light?

and that you have very good ground connections at every light?

 

I also suspect you have the stop/turn lamps wired to the dimmer running lamp side of the bulb so when you flip on the headlamps the brighter filament drowns out the signal and brakes. Quick way to check it to turn the running lamps on and hit the brake pedal and see if the lamps intensify. The lower wattage filament may not draw enough to trip the flasher.