I recently purchased a 2001 Subaru Forester S. It has aftermarket key fobs and remote start. The security light never comes on and I don't think the alarm is working. The keyless entry works and the parking lights flash, no horn.. I have a feeling the remote start is aftermarket and they may have damaged or disarmed the system. I haven't checked the bulb yet. I suppose that's next. If anyone has any suggestions for me on how to troubleshoot this problem I would appreciate it. Thanks

maybe you can find a brand/model of the remote start system and locate a manual for it on-line?

 

It may be OK if it was professionally installed, but many people have problems with them and it's usually worse if some DIYer did it.