When the "D" series Tractors first arrived on the scene, the wiring as well as the switches were not the best used for the load the systems had on them.  In the D10 & D12 Tractors AC used a garden tractor switch to control power on board the Tractor. These switches usually only had 4 blade terminals on the rear of the switch and having more than 4 circuits coming into the back of the switch from different points on the Tractor overloaded that switch. To keep costs down, AC engineers decided to "piggy back" circuitry to that switch. Not a good idea! In the Automotive electrical world, we call that "stacking". When you stack circuits on the rear of a switch that cannot handle the heavier loads, you get high resistance in the circuitry. High resistance causes heat, and if the circuitry gets hot enough, components start to melt!! Hence the case with the "D" series Tractors that had to light of a Ignition switch to handle the heavier loads required for the system to do. This is why so many "D" series Tractors wiring was so cobbled up over the years! This is the reason why we offer a much heavier Ignition switch as an option to those customer's that do not want to deal with this issue. Who wants to burn up a brand new wiring system? With heavier built ignition switches, the amperage is higher and more circuitry can be connected to the rear of the switch safely to handle everything on board the Tractor. We offer a 7 blade HD Ignition switch for the D10, 12, & 14 model Tractors, (6 or 12V) and an 11 blade Ignition switch for the D15-19  12 volt Tractors that have more circuitry and components.  When renewing your wiring system, renew the junky OEM ignition switch as well! Also, when you order the optional key switch,  we wire up a complete new plug that plugs right to the back of our new switch!  No stacking! No low voltage! No burning wires!

B&B 50 amp 11 blade Key Crank Ignition Switch-

B&B P/N-1501-11    $45.00 

B&B 40 amp 7 blade Key Crank Ignition Switch-

B&B P/N- 1501-05F  $55.00