Symptoms:
- Fall of 2017 one incident of all external lights not turning off. The switches didn’t affect it and pulling the fuses didn’t shut it off but unplugging the brake controller did.
- After this, the left rear taillight stopped working as a marker light but it still works with brakes and left turn signal.
- After this, I noticed a parasitic drain on the battery. Deployed in Feb 18 to Nov 18 and truck was in storage.
- Parasitic loss has gotten worse and the truck will often not go more than two days unless it is run that day or the battery is disconnected.
- Since Nov18, the 4WD position light stopped working. I replaced the sensor but it didn’t fix the issue. No dash light illuminates regardless of the position of the 4WD lever. I thought it might have been the locker bypass but I unhooked it and still have issues.
- Most recently, the mirror defrost light blinks constantly but it still works as it should
What have I tried/checked?
- I used a meter in series with the negative terminal to confirm a significant draw at ignition off. I suspected the TIPM so I pulled all fuses in the TIPM with the meter connected and no change.
- I pulled the TIPM and checked the internal board and didn’t see any burned connections.
- I've checked lights, tried unplugging various connections under the hood, checked the alternator, the starter, the smart bar and the winch.
- I even took it to the dealership and they couldn't find it.
It's not throwing any codes or indicator lights. I still get no light when I shift the transfer case, even though 4LO lights up with the bypass switch.
