What prevents fire hydrants from freezing during winter?
If you are so afraid buy Turpenoid its not supposed to be as bad as the original stuff. I use it, its fine. I don't have 8 legs or cancer. I don't wear gloves. Just try not to clean them in a closed room like a bathroom and don't pour it down the drain. Don't leave it on your skin for a long time.
That sounds like an aftermarket alarm, which means that it was installed after the truck was bought. Best bet is to find a company that installs car alarms ask them if they can locate it remove it. But, as the alarm is apparently hooked to the ignition, the removal has done carefully so you don't fry the computer.