08 f150 remote start

just a quick question, will be installing a remote start/keyless entry in my truck this weekend, been a long time since ive done a remote start. the question is where are diodes needed? i plan on using the remote start,keyless entry, and an Aux to turn on drivers seat heater. ill be installing a compstart c800-s

thanks in advance

Diodes are generally needed when connecting multiple sources to a single input. For example:

Say a car has 4 separate door stat wires (when you open a door, the car knows specifically which door is open). Your remote start or alarm doesn't care which door is open, just that all the doors are closed. Thus, the RS/alarm will only have 1 door stat input. To connect all of the door pins to the single door stat input on the controller -without- having the car think every door is open any time one door is open, you have to diode isolate each door stat wire. If the car has negative door pins (fairly common; wires show ground when door is open), you'd connect each diode with the stripe facing the controller (ground can only "travel" into the controller, not back into other door pin wires).

There are other uses for diodes but they aren't all that common. Occasionally, your bypass application guide may call for one and it's probably a good idea to use them with relays to prevent voltage spikes back into the controller (google flyback or snubber diodes). I guess technically, you could put them on any input/output that only acts in one direction but that'd mostly be a waste of time.

thanks, that sums it up nicely for me, ill pick a few up just to be safe