Originally posted by netZ
what remote start alarm system are you referring to?
for the viper 550esp and other dei remote start systems, there's a black/white neutral safety wire that needs to see ground before remote start will work. you tap the neutral wire off the ecu. you should put a toggle switch between this wire so that you can disable remote start whenever the vehicle is being serviced or in parked places where you don't want the remote start to be accidentally enabled.
the viper 550esp has a remote start status output that can be used on a relay to 'engage' the clutch to allow the starter to start. this is the blue wire off the remote start harness. this wire can also be used to re-arm a factory alarm, this doesn't apply for this application usage.
Thanks for the reply. I was hoping you would jump in on this. I am putting in a DEI unit.
The problem with wiring the neutral safety wire from the ECU directly to the black/white wire is that the ECU throws 12V in neutral, and 0 (ground?) in gear, so it would have the opposite effect, hence the two relays.
Regarding the status output (blue) wire, do you know if it transmits before or after checking the neutral safety wire? Thanks again.