Hey Rubi:After reading through this entire topic; this is my summation of how to modify a 2018 3.6l to run without an aux battery and not have to have it reflashed at the dealer as detailed above. Anybody, please correct me or add any additional steps not called out below
Disconnect the power control relay connection from T3 fuse block terminal, wrap it with electrical tape or completely remove the relay from the vehicle.
Disconnect the positive lead connection at the aux battery, reconnect this lead to the main battery.
Disconnect the negative aux battery connection, wrap it with electrical tape
Additional question; can the the aux battery main positive cable be easily connected to the main battery? Please explain exactly what has to be done to accomplish this reconnection.
I also disabled ESS through the hood open switch. I will also be removing the aux battery from the vehicle.
Let's look at Jerry's diagram:
Requests for power from the ESS/Aux battery initiate at point N1. If you, with low gauge wire (i.e. thick) and high amp fuse connect N1 to N2, you will redirect power requests from the ESS/Aux battery to BOTH the main battery and the ESS/Aux battery. This is because N1 will now "shout out" to the ESS/Aux battery and N2: which is connected to the main battery.
This brings up to step two:
Disconnect the negative cable from the ESS/Aux battery to the main battery. Now all requests for power from the ESS/Aux battery, which again, originate out of N1, get rerouted to N2, the main battery. Jerry's diagram features a beyond factory on/off switch because he was demonstrating features he was introducing in this post , but the concept remains the same. Two big wires come off the negative post of the main battery. One, which you'll leave along, runs to the body ground. The other, which you'll yank, comes from the ESS/Aux battery.
Once disconnected, cover this cable end coming from the negative terminal of the ESS/Aux battery with electric tape (as I think you mentioned) for me, okay?
So we're clear, your question "can the the aux battery main positive cable be easily connected to the main battery? Please explain exactly what has to be done to accomplish this reconnection."
is yes, hardwire N1 to N2.