I would not recommend that.
The glow plug circuit is actually feed two different ways.
First condition is a preheat, it's feed through the glow plug indicator, along with letting you see it heating, it also keeps for over Amping the glow plugs and burning them out.
Second condition is starting, where the glow plugs are feed straight without the glow plug indicator in the circuit.
The stock switch does this for you, fix it and you will be much better off.