Tail lights and signals going whacko.

[mike's1965]

Truck has been parked for years, trying to get it back on road, my biggest issue now is turn signals not working, this was not a problem before parking truck.

Trying to get it from my mom's to my place, but can't until the tail lights, signals work properly.

Turn on left signal, both rear signals flashing, I think right signal makes left signal flash too.

Took off uhaul trailer wiring harness that had been on 15 years, cut back some wires to get fresh wires, anyways after taking that out and hooking the wires back up, it's still doing this.

Also driver's side front blinker not working, bulb fine, also front parking lights not working when switch pulled out one click.

Could a bad bulb cause any of this?

Any ideas what to check next time I come over?