Old Viper alarm system
 

I have a 1983 380SL with a Viper alarm. The remote has two buttons but only one seems to operate the system. When I activate the system the doors and trunk lock and the alarm arms and I get one chirp type sound and when unlocking I would get multiple chirps. Recently the doors & trunk continue to work but I get no chirp sounds and the alarm does not activate, any ideas would be appreciated. Also I would like to know where the components are located so I can check connections ect.
Thanks Harry Crim Tucson Az.

DEI made the system, but there are so many different models, it's impossible to know what system you have. You'll have to dig up the "brain" and run some diagnostics from there. That location depends on the installer. Most people bury it behind the dash somewhere.

99.99% of the time the old system is just plain not worth spending any time or effort on. With new ones being less expensive than repairs and MUCH better, it makes no sense to fix the old one.

Do you know where the "valet" switch is? That is the first step to finding the brain, as there will be a wiring harness leading back to the brain. A high quality install will have the valet switch buried into a factory style loom to throw thieves off, so it might take some time and effort to find your way around.

We used to fully remove the dash to install the brain (if the bad guys get to the brain and the starter-kill, they win) and it takes some real work to get to it. We didn't usually put DEI stuff too deep, as they were middle-of-the-road systems and could require getting too.