1996 chevy silverado alarm going off and truck won't start

[cadens03]

Hey everyone, as stated in the title my 1996 chevy silverado's alarm has been going off constantly and only turns off when I disconnect the battery, the truck also won't start and I hear a clicking noise under the dash when I'm inside the cab. I have looked for others with this problem but haven't found anything online. There are no lights on the dash for any security or anti theft devices. Please let me know if you have any suggestions!

 

[east302]

It sounds like an aftermarket alarm, so there should be a box of some sort jammed up under the dash. If it has the brand/model number on it then that may make it easier to remove but, otherwise, you’re left with tracing all the wires from the box and removing/repairing the splices into the factory wiring.

 

[HotWheelsBurban]

Hey everyone, as stated in the title my 1996 chevy silverado's alarm has been going off constantly and only turns off when I disconnect the battery, the truck also won't start and I hear a clicking noise under the dash when I'm inside the cab. I have looked for others with this problem but haven't found anything online. There are no lights on the dash for any security or anti theft devices. Please let me know if you have any suggestions!

Sounds like it has a kill switch somewhere that needs to be defeated or worked around. The purple wire should be the one for the ignition circuit, that activates the starter solenoid. Chances are, that circuit is interrupted for that kill switch, and until you bypass it, it's not going to start.
My crew cab has an aftermarket alarm, and after it was parked for three weeks and the battery went down, I got it started with a jump box. Ever since then, you have to hit the kill switch magic button or the truck will not start. I think if I disconnected the battery and let it sit for a bit before reconnecting it, I might be able to get it out of this mode. On the other hand, it might make the situation worse....

 

[someotherguy]

'96 doesn't have a factory alarm so it's definitely aftermarket. Typical installs will interrupt the power to the starter, so if your alarm is no longer working properly you'll need to remove it and reconnect the factory wiring where they tapped the alarm in. It's not complicated work, but if you're not familiar with automotive wiring you may want to have an alarm installer go after it so that you don't cause yourself bigger headaches.

If you're reasonably decent with wiring I suggest looking up in this section for the post with the service manuals you can download for free; the wiring diagrams are in there and you can use them to identify what has been tapped into. Sometimes it's just as easy as finding the non-factory looking module under the dash and examining it carefully before snatching it out and re-connecting the factory wires where they spliced in.

Richard