Ok so last night I installed off road lights and I disconnected the battery. And it was running fine. I then went up to work and turned it off. The next thing I know, it is going off like crazy. The theft light was blinking, the head and brake lights were flashing, every light on the dash was blinking, and the horn was going off. Then it wouldn't roll over to even start it. So I had to leave it in town with the battery disconnected. Can anyone please explain why this happened? It would be much appreciated.

 

Sounds like the truck thinks its being stolen do you have keyless entry (factory alarm)

 

It has some kind of after market security. But the guy that I bought it from said it was on when he bout the truck at the dealership.

 

Aftermarket with an auto start or just a security system

 

Just a security system

 

Look under the dash for a box of some kind that has a lot of wires coming out of it I doubt it's tucked up nice it probably has four or five sets of like 22-26 gauge wire coming out of it in all different colors unplug the set that has a red and black thats the power to the security box or if your unsure unplug it all just take pictures so you know how they go back in and try and start the truck