Reading through this whole thread, you would think it's very complex thing to do. But you are correct, just pull the white wire off, tape it, and hook your switch in to where the white wire used to be and then ground the other side of the switch. You can even leave the blue wire connected.
Some of these threads are throwing in the earlier trucks that had a different glowplug system. To convert them is a little more involved but if you have the later glowplug system with the relay at the back of the engine, it's as simple as the original thread starter explained.
You are only powering the coil on the glowplug relay, so the wire does not need to be very large. Since you are GROUNDING the controller relay with the new switch, a fuse is not required. The worst thing that could happen, one of your new wires rubs a piece of metal and the glowplugs stay on all the time. A fuse is not going to help in this situation, and it will cause no harm except most likely burnt out glowplugs.
