Viper 771 xv aux wont work right

I have a viper 771 xv LED alarm/remote start. I am trying to use one of the 3 aux channels to set off a latching relay and in turn will turn on underbody lights. With it all hooked up without the alarm as a signal(touching the trigger to +) it will work fine. but if i use the - pulse from the alarm, the relay cuts on for a second and cuts back off. Almost like the signal isnt long enough to fully latch the relay. BTW the relay is in a 93 grand am and the alarm was professionally installed. and before anyone asks, the relay IS latching and has been programmed to latch on a pulse and turn off on another pulse, (PAC TR-7) thanks

you can program the output on the alarm to be latching

i fixed it using the relay, but how do u program it to do that? Bitwriter?

look your install guide it tell ya how to program, a bitritter is just a lot easier to use.