2004 Trailblazer

Getting ready to hook up an Autopage 615 remote start unit to an Autopage 615. Never done one of these before, and by looking at the 2 bypass modules, the Omega IB-GMBP and the DEI 455G-W, both of the interfaces hook up to the purple wire on the OBD. My question is, do I have to isolate these wires from each other, or do I need to take any other precautions when hooking these to units on the same wire?

"My question is, do I have to isolate these wires from each other, or do I need to take any other precautions when hooking these to units on the same wire?" The (2) purple wires that go to the data connector do NOT have to be isolated. If both modules have a brown wire (usually ground when running) you will want to isolate these 2 wires with diodes. Mike