This is not a modification...just clarification...
Our water heater is under the bed on the driver's side.
Note: there are NOT three valves on the water heater plumbing in our 2003 RT Chevy Popular...
a hot, a cold, and a bypass valve. Rather, there are just valves for hot and cold.
Therefore, use the hot and cold valves to bypass...open, water goes through the heater...
closed, it bypasses the heater.