Left side of the tank, right side when you're facing it. If you're having trouble against them their primary frontal weakspot is the hull MG mount, unless it's been strengthened considerably since I last played ground forces.
Also, if they're facing you at an angle shooting around the point where the side armour connects to the frontal armour will detonate their ammunition rack 9 times out of 10.
Edit; By the way guys, feel free to add me in Warthunder, my IGN is Tokthree and I'm always happy to join a squadron if I'm online. I can play up to r5 German, r4 American/British and r3 Japanese/Russian aircraft and up to r4 German ground forces. I can play RB and SB in ground forces and AB and (if you'll deal with my inexperience) RB in air battles.
I can't play right now as I'm going to bed but if you see me online don't be afraid to ask me if you want to squadron up.