Just bought a Dakota, when you start the engine there's an alarm similar to a seatbelt alarm but a different pitch. Beeps like crazy for about a minute then stops. I've disabled all factory alarms but it still beeps. No corresponding lights on the dash, my mechanic thinks it's something aftermarket. How do I even begin to find it? Thanks

 

Moved to the correct section.

While it's beeping, find the beeper. Unplug it or disconnect it or cut the wires. Find another mechanic if he can't figure that out.