ITS UNDER THE FLOORBOARD OF THE PASSENGER SIDE, BUT INFRONT OF THE FLOORBOARD, WHERE THE PASSENGERS FEET WOULD NORMALLY BE PLACED AT WHEN IN THE PASSENGER SEAT. PULL THE CARPET UP FIRST. ONLY PARTIALLY, THAN USE A 10MM SOCKET WRENCH TO TAKE THE 4 BLACK 10MM PLASTIC BOLTS OFF THE FIBERGLASS PASSENGER FLOOR BOARD. THAN PULL THE PLASTIC KICK PANEL OFF, 1ST BY PULLING THE RIGHT SIDE PLASTIC KUCK PANEL OFF. THAT RIGHT PASSENGER SIDE PLASTIC KICK PANEL WOULD BE LOCATED WHERE THE PASSENGERS RIGHT FOOT WOULD GO AT, BUT ON THE WALL UNDER THE DASHBOARD AND INFRONT OF THE PASSENGER RIGHT SIDE DOOR. ONCE YOU GET THOSE 4 PLASTIC 10MM BOLT'S OFF THE FIBERGLASS FLOOR BOARD, YOU CAN PULL THE SEAT BACK ALL THE WAY USING THE PASSENGER SEAT SWITCH, THAT ALLOW'S THE SEAT TO GO BACK AS FAR BACK AS YOU CAN GET IT. ONCE YOU PULL THE FIBERGLASS FLOOR BOARD UP A LITTLE, PLACE SOMETHING UNDER THE FLOOR BOARD TO HILD IT UP UNTIL YOU GET THE AUXILIARY BATTERY OUT, BUT BE CAREFUL NOT TO LET THE AUXILIARY BATTERY TERMINAL'S POSITIVE AND NEGATIVE TOUCH METAL, WHICH MAY CAUSE A BURN TO YOUR SKIN OR WORST, A FIRE IS POSSIBLY A EXPLOTION, THEREFORE BE VERY CAUCIOUS WHE. REMOVING, STORING OR HANDLING AND TYPE OF BATTERIES, THERE IS ONE OR TWO NUTS HOLDING THE AUXILIARY BATTERY DOWN IN A BRAKET TO GOLD THE BATTERY IN PLACE, MAKE SURE YOU PUT THE NEW BATTERY IN, CAREFULLY AS WELL, NOT LETTING THE TERMINALS CONTACT ANY METAL OF ANY TYPE. PUT THE BATTERY IN, IN REVERSE OF HOWYOU TOOK THE BSTTERY OUT. THERE IS A PLASTIC FOOT PANEL ON THE FLOOR, WHERE THE DOOR OOENS AND CLOSES AS WELL. THAT NEEDS TO BE OULLED UO BY HAND, AND THERE SHOULD BE ONE PLASTIC 10MM BOLT ON THAT BRACKET AS WELL. BOLT THE NEW BATTERY IN PLACE, BOLT THE BRACKET BACK IN PLACE, PUT THE POSITIVE RED TIP AUXILIARY BATTERY TERMINAL BACK ON THE CORRECT TEEMINAL'S AND TGE BLACK NEGATIVE TERMINAL BACK ON THE NEGATIVE AUXILIARY BATTERY TERMINAL. AFTER THAT, PUT THE FIBERGLASS FLOOR BOARD PANEL BACK ON. AND PULL THE CAROET BACK DOWN AND PUT THE KICK PANEL BACK UNDER THE RIGHT PASSENGER SIDE INFRONT ON THE PASSENGER DOOR, AND PUT THE OTHER RIGHT DOOR FLOOR PANEL BACK ON THAT SBNAPS BACK ON SLOWLY AND CAREFULLY NOT TO BREAK ANYTHING AND YOUR DONE. HAVE A BLESSED DAY.

I find it odd that MB couldn't have put this auxiliary battery in a more convenient place like the rear cargo hold next to the spare tire especially given its small size.