I have a M20K (25-1187) and had the electric fuel boost pump overhauled within the last two months. I sent it in for overhaul because it was leaking a little fuel, and during descents I could smell fuel in the cockpit...it got more prevalent with the landing gear in the down position. My A&P found evidence of the pump leaking fuel. Although it was a small amount of fuel it was time to send it out...it was the original pump that has never been overhauled according to the engine logbooks. Before I sent it for overhaul, all of my fuel boost switches worked fine (Low Boost, High Boost, and Prime switch). After I got it back from overhaul and installed the pump, all Fuel switches work except for the Low Boost Switch??? All three Boost Pump Switches (LOW, HIGH and PRIME use the same electric fuel pump I had overhauled) I'm looking for help to resolve this issue. Any thoughts on this would be more than welcomed!!! Thank you.