Front turn signal question

[mac6150]

I know the turn signal issue has been beat to death on the site, but I have a question. I have been having turn signal issues after buying the 72 F250. I finally replaced the turn signal switch and all issues went away. Its a miracle. But now a new issue has arisen. When I have the lights on the front signals do not work, the parking lamp is on, but no signal. The turn signal works fine when the head lights are off. So what is different? The signal worked before when the headlights were on. It should be noted that shortly after I bought the truck I replaced the bulbs with Halogen bulbs and added new wiring and relays, which work great. I also replaced the existing bulbs with LED bulbs, which as I stated above, worked fine before the new switch but now has that issue. Has anyone run into this issue before? I haven't started trouble shooting yet, that will be for this weekend. I'll probably swap bulbs out and try the old ones and see if that solves the problem. But other than that, everything else is working fine.

[sargentrs]

Did you also replace the stock flashers with LED flashers?

[Busboy]

Weird stuff can happen when you have a bad ground from the bulb to the bulb socket.

[mac6150]

Yes, I replaced stock flashers with LED. I'll replace the bulbs this weekend and see what happens. Just odd how with headlights off they work fine. with lights on, back works fine, just a solid light up front. Oh well, gives me a mystery to solve. I'm fairly sure it has something to do with the LED bulb.

[markguiver]

I'd check the grounds first. That's normally what causes strange issues with these old trucks. I installed a common ground post on each side, front and rear with star washers against the metal to get a good bite. Ran the ground from each light to the post, and haven't had any issues for almost twenty years.
Mark.