The short answer is yes. The long answer is that there's a specific way to do it. You can't just hook up cables to the main battery like you would any other vehicle. I'm hoping to do a video on this but in a nutshell, you'll need to hook up to the negative terminal on the main battery but then you'll need to attach the positive lead onto the positive terminal on the fuse box. This would be the first 2 studs that sit closest to the main battery. The fuse box lists these as N1 and N2. The aux battery is actually what starts your JL.
Last week I was out of town.. 225 miles away from home. Went out to start my 2 dr JL and the battery(2) was dead. 8.4 radio screen was black, no lights and it appeared that no 12v power was getting to the JL.
Well, I knew I was going to have to try to jump start. My plan was to use N1 for pos and a chassis ground point in order to jump start. I was going to do this as I have been following the JL forums for months and had the impression that no way your could jump start a JL the regular old way even though the JL manual said you could...
So, flat bed guy drives up with his brand new rig. We talk and I tell him the drill and the issues I thought in regard to jump starting a JL. He had never jumped a JL before.
He had a freshly charged 12v power pack with him. I told him try the regular old jump start way, just for shits and giggles to see what my JL would do. Well, he hooked up the power pack and low and behold, the dash lights' radio lit up but the JL would not turn over. Was like the power pack did not have enough omph, lets say.
So, my next thought was just use jumper cables and jump from his new truck's 12 v system. He got the jumper cables out and I said, for the heck of it just jump it the regular old way again. WELL, with the dual battery 12v system he had and the battery cables to my JL the regular old jump start way, the JL frigggin started right up, like nothing was ever wrong.
I had planned to use N1 but never needed to...
In closing, quite possibly all the JL forum guy's that said they could not jump start the regular old way may indeed have been able to do so If they had a better 12v source to jump with.
I'm just telling me story here. I am clueless ... pretty much as most if not all other JL owner's are in regard to jump starting a JL. Geeeez, maybe it is as easy as the JL manual states.... ???