Call of Duty Zombies really enjoys its side objectives and Easter eggs. There is almost always out of the way that will require you to do a little exploring and find parts to craft something that will aid you as you fight for your life. Mauer Der Toten is no stranger to this concept with the inclusion of Klaus, a robot made by Americans but with a German personality. Here is how to activate Klaus the Robot in Mauer Der Toten in Call of Duty: Black Ops Cold War Zombies.
Before you can start up Klaus, you need to both turn on the power and activate the Pack-a-Punch machine. When that is done, go into either of the yards by Pack-a-Punch with the search towers in them. There will be piles of debris scattered around both yards that you need to interact with to dig up. Eventually, you will grab a Microwave Dish from them.
For the next part, you will need to have a weapon with the Brain Rot effect on it. You can purchase it from the Pack-a-Punch machine for 2,000 points. Now go into the hotel building and enter Hotel Room 305. Using your Brain Rot weapon, turn a zombie onto your side, and it will destroy the door with the hole in it. Walk into the room, it opened up and grab the robot hands from the corpse on the bed.
For the last part, you need to kill a Panzer Soldat. One will drop in at round 10 every game. When it is destroyed, pick up the Battery it drops.
Now there are two spots you need to go to. First, enter the Garment Factory, and you can install the Microwave Dish on a device in there that will allow you to control where Klaus goes when you activate him. After that, go to the Safe Room and interact with Klaus to give him his battery and hands. Be careful; even though Klaus will help you shoot, it takes him a little bit to get started up and go through his introduction announcement, so don’t get yourself swarmed and overtaken trying to watch Klaus.
When Klaus is activated, you will lose your tactical equipment and, in its place, be given a remote control for Klaus. With this, you can set Klaus to go to a specific location to defend. When you want him by your side, cancel the action, and he will return to you.
Klaus will not stay with you forever. After about two minutes of him following you around, he will return to the Safe Room, where he will sit and recharge. When done recharging, you can spend some points to activate him again for another session.