viper 791xv , voltage sensing 07 sierra

2007 Sierra CLASSIC 2500hd 4wd 6.0 Viper 791xv w/ remote state hooked up. I had this installed a few weeks back and have been fine-tuning this to my likings. I will add the 520T later on in the future.    During the installation I forgot to have them install the hood pin.   The install shop suggested that I simply add the under-hood light that has the mercury tilt switch (OEM on 99-01? C/K trucks).   I added this and wired it in to the underhood fuse block.   It is on a 10 amp fuse. I was told by adding this would eliminate the need for a hood pin as when/if the hood was opened the light would turn on and trigger the alarm. This is not the case.   Any voltage drain (lights, whatever) will not trigger the alarm.   The only triggers I can get is shock & the doors open. The doors are wired into the interior lighting. So how do I get the voltage drop sensing turned on for this unit? Thanks for any help provided. Alex Mighty Hd

there is no voltage drop feature on this alarm. however there is a dedicated hood pin (-) input wire on this alarm. it is a gray wire in a 6 pin harness

How could I go about wiring the light into the hood pin trigger on the alarm?     Thanks again for the reply! Mighty Hd

Got it wired up today.    I ended up using a hood pin.   I could not get the bearing tilt switch to trigger when the hood opened up.   I believe it may have been a faulty unit.    Regardless the pin works flawlessly. I do appreciate the help and replies. One more question.    I had an 04 sierra with a viper 500 and the 457gw module.   When the system was armed, the alarm siren and horn would chirp.   Full trigger of the alarm only the siren would sound. What do I need to wire to be able to get the same with the 791?    I'd prefer both the horn to honk and siren to sound off.   Is this possible?      I triggered the alarm today with the drivers door open and the horn and siren both went off, once the door is shut and you get a full trigger, only the siren sounds. Any further advice/suggestions is appreciated.    Edit:   I also have the DIC settings to honk the horn upon arming.Mighty Hd

Anyone?Mighty Hd

if it's a newer 791, it has a horn output in a 2 pin harness on the side opposite the large 12pin harness. otherwise it if's an older 791 then you'll have to use a relay off the siren output (brown in the large 12 pin harness) to trigger the horn also

Stupid me. The reason why I didn't see the horn output harness because it was not in the box with the alarm. How would I go about getting a harness??Mighty Hd