Alarm install, ignition wire, 72 F250

First post. Found this site while searching for info about car alarm installs. This is my first install of an alarm. So, I'm installing a Viper 3105 Keyless entry Alarm system in my 1972 Ford F250. (I got the truck for about 3 times what I paid for the alarm, hehe) I think I have most of it figured out. I'm not using the trunk/hood wire, the extra channel wires, the negative trigger wire, or the orange ignition cutoff wire and have cut them off about8 inches from the plug to be taped and zip tied. I also have a separate relay to control the door lock actuators. My first question is, do I need to use the yellow wire for ignition on power? If so, what does it do? On the Viper harness main plug, the yellow wire and orange wire came pre-connected to what I am guessing is an ignition cut out switch/relay. That assembly has a second yellow coming out to hook to the ignition switch, and two wires that I am guessing go to the ignition system to keep the car from starting. I don't plan to use the ignition cut out, so do I still need to connect the yellow wire? Second question, because my truck is a single wire positive dome light system, I am connecting the dome light supervision wire and the positive trigger wire to the dome light supply wire. Is that correct? Any help would be appreciated. Clint

The ignition connection is how the alarm system detects when the key is switched on. The ignition connection will trigger the alarm if the key is switched on while the alarm is armed. Also, the ignition connection is needed to program the alarm, put it into and out of valet mode, and disarm it if you lose/break a remote, because all these actions require turning the key. If you use the dome light supervision feature, the ignition connection shuts it off when you start the vehicle--otherwise it will stay on for a full 30 seconds after disarming. As for the door trigger: you should connect the positive trigger wire to the vehicle's dome light wire, but don't connect the alarm's dome supervision output directly to this wire, as it's a negative output. If you want the dome supervision feature, you'll need to use a relay.

Ah, ok, so definitely need the yellow wire. I'll have to go buy a relay for the Dome Light supervision. Thanks.

Ok, got everything all hooked up and so far the lights flash, the alarm chirps 1 for locked/armed and 2 for unlocked/disarmed, the dome light comes on when unlocking/disarming, and the door locks lock and unlock as advertised. The panic button sets off the alarm. Now, the problem is, the blue LED stays on constantly and when I rock the truck the alarm just gives me a series of chirps. Seems like I may be stuck in Valet mode. I tried the ignition on then off then pressing the button, LED still on. Tried opening the door then hitting the remote lock then aux then lock buttons, LED still on. Any help would be appreciated.

Are you certain that you have the small white and blue plugs (from the antenna cable) connected to the right ports on the alarm brain? The blue plug should connect to the blue 2-pin port on the same end of the alarm as the antenna plug; the white plug goes into a port on the other end. The blue plug should have a gray wire in it; the white plug should have a pink wire.

AHA, I thought all three went on the same end, I'll move the white plug...

Yep that fixed it. Thanks for the help.