The glycol tank is located in the back on the drivers side. If you are in the trailer facing the rear, on the end of the headboard shelf to your right is a triangle wood piece held in by a couple of screws. You need to remove this piece of wood. The tank is behind there. Please see the following video. https://www.youtube.com/watch?v=WauzRYpGhhg&list=PLCMrvBGaOplpkvlu_zIsW-YZdR_qelvxo&index=1