86 chevy c 10?

whats up, i just joined here, seems to be alot of good infor here also. I have always been into stereo, and have done alot of installs for myself and a few friends. Now, i have an 86 chevy c-10 truck, no power windows or power locks. I have read alot and have always had local shop do my alarms, but since I am doing everything else in this truck, I was going to attempt to put alarm on. I did put an alarm on an s-10, but it was just wired to shaved door actuators to pop door open, thats all buddy of mine wanted it to do and it worked. My question is on the truck i am working on now, it did not come with factory interior light, it has aftermarket light in it, but it does not come on when door is opened. There arent any triggers or buttons, it has to be turned on manually. Now most alarms I have had worked off interior light, can i just install door pins and have alarm triggered by those? Or what would be best way to do that? thanks for any help, and sorry for long post86 Chevy, FI BL loaded 12", sundown saz-1500d, sax-100.4, premier 800prs, 2 sets cdt components

Look in the door jamb between the door hinges.  There should be a small plastic cap covering a hole.  Or maybe just the hole is there.  It should already be threaded to accept a pinswitch.  Go to the dealership and purchase the original part.  It will be much more reliable than any other pinswitch.  And the last time I bought one they were only a few dollars.  When you get it from the dealer it will appear to stick out way too far.  Simply install it in the hole, close the door and it will adjust to where it needs to be.