I am working on a circuit and I need to divert the current to higher resistance components in parallel without changing their voltage input. There are 4 thermoelectric devices (T1, T2, T3, T4), a heatsink, and a pump. They all ideally need 12 volts but the heatsink needs 0.09 A, the fan needs 1.1 A, and the thermos can take any current. The battery is 12V and 2.9 Ah.
Since the thermoelectric devices have such a relatively low resistance, nearly all the current goes through them and none will go through the pump or heatsink as shown in the schematic below. Is there some component that will help divert the current to the pump and heatsink? We are avoiding using extra batteries due to the weight and ease-of-use.
We have run out of ideas since we have limited experience with circuits. Any suggestions would be greatly appreciated. Thank you!