EZ-TCU 302820 wiring ground question

[brad33478]

I have my ez tcu and everything is working fine and I have it all wired as instructed, but when i disconnected my main ground cable at the battery and leave the tcu ground i noticed my lights in the cab were still on then realized it was back feeding and grounding through the ground wire for the TCU. is this normal or is there a bad diode in the hardware or something?

[TCITech1]

I'm not sure which ground wire you are referring to. There should only be one main ground going straight to the battery.

[brad33478]

yes that is the ground wire I am talking about, my issue is that when I remove my TRUCKS ground cable (but leave the TCU ground to the battery). It tries to use the TCU ground to ground the battery. (My cab lights stay on when I remove my TRUCK ground @ the battery but leave the TCU ground).

[TCITech1]

I honestly have no idea why it is doing that. I don't know how your truck is wired. It sounds to me like there is a bad ground somewhere on the chassis. There is a back feed situation going on somewhere where there shouldn't be. If our wiring harness is wired straight to the battery, there's no way it can power your accessories of the truck.

[brad33478]

it has me really puzzled, nothing is killing the battery overnight but if i remove my main ground, lights stay on. remove the TCU ground wire @ the battery they shut off. no problem so far so I guess ill just let it ride and leave my grounds hooked up
thanks