2001 EZGO TXT Lighting Issue

[Monroe]

I have a new to me 2001 EZGO TXT with a rear light problem that I cannot figure out. The previous owner installed a front light bar, new LED taillights, turn signals and all new wiring harness. All lights work as they should during the day when the headlight switch is not on. However, when the headlight switch is on only the headlights and front marker lights work properly, turn signals/hazards no longer work nor do the brake lights or rear running lights. I have traced all wiring and all connections look good as well as fuses. I am wondering if possibly the LED taillights could be causing the problem or even the flasher, which is a standard two prong NOT a high power electronic. HELP!!!