Retrofit kit burning

I just bought a retrofit kit. Before I installed it, I turned off the power source and took our the backup battery.Also made sure the resistance is lower than 5200 ohms.WhileI'm installing, The wires that connected to the retrofit started burning.Burning smells and smoke coming out from the retrofit. I had to cut the wires to stop it. I'm not sure if my retrofit is defected. I think there is risk of the product catching fire.