Varad Scanner hookup

Trying to hook up VS4000B to activate with alarm when armed (Vampire 2020 3 Channel) in 1988 Jeep Wrangler.  Red to 12V Constant, Black to (-) ground, and yellow to orange starter disable wire, 500 MA Neg. output when armed , from alarm. 

Problem, the scanner activates when the engine is turned off.  At this point the scanner remains active when the alarm is armed and unarmed.  It does go off, when vehicle turned on. 

After seeing other responses to similar questions on site I placed a diode in between alarm and starter on orange wire with cathode side toward alarm.  LED yellow wire connected in between alarm and diode, but scanner would not activate.  Placing the yellow LED wire between diode and starter disable causes scanner to activate and remains on with alarm when armed and unarmed.  Any ideas how to have scanner activate only when alarm armed??? 

you don't have to put the diode in the relay, put it on in the orange wire.

cut the orange wire one side goes to brain the other goes to the relay. Put a diode with the cathode side facing the brain.

Now put the yellow wire in the brain side.

that problen that you have is that the led is reciving a back feed fron the ignition. the diode is stoping the back feed . good luck.