97 chevy blazer CS-2011RS

Negative current flows through a diode from the band (cathode) to the other side (anode), so on your door trigger input wire face the band away from the alarm brain, and for the illuminated entry output, face the band toward the alarm brain.  This will solve the issue of setting off your alarm like Player69 said. 

However, If you want to shut your light off immediatley just like they do when you lock your doors with the factory remote, try this:   if you want you can use your lock wire to pulse the wire that turns off your dome light.  This is very easy with neg door locks like I have, but you would need to use a realy since you have positive door locks. You would also need to diode isolate this wire with the band facing the lock wire or the relay in your case, or maybe not, I guess I can't really think of a scenario that using a diode would prevent, but it wouldn't hurt.  You definately need one with neg door locks though so the dome light turning on doesn't lock your doors.

How much is there to understand about diodes(power only flows one direction). Now stop and think about this for a second, I will be hooking the (-) trigger input wire to the white (-) dome light wire with a diode(cathode on alarm side) and hooking the (-) dome light illumination output to the same white wire with a diode(anode on alarm side). Ok my vehicles dome light stays on 30sec after you shut the door, so if I arm my alarm before the light goes out it will bypass the door trigger because even with a diode the (-) input trigger wire will show ground to the alarm.

According to my information, there is a TBC module mounted to the heater unit or on the right side of the steering column.  At this module: drivers door is tan - at B4 possition.Passenger door (and back doors) is orange at B2 position.

I don't know how acurate this is as this is for a 98 not a 87.