Air Bab light on.....again!
 

Ok, I had my '99 at the dealership 2 months ago to have them re-wire the seat belts as the air bag light stayed on. Everything was great until we went on vacation, after sitting for 2 weeks...air bag light is on....The dealer checked it, no faults and turned it off (no charge**surprise**) Yesterday the air bag light pops on again after only sitting for 2 days. Any clue on what could be going on? voltage issues?

The issues with the airbag are threefold ...
 

... there's the bad seatbelt buckles, problems with the connectors and problems with the wiring harnesses.
When you connect the PST-II or the PIWIS to the car it will tell you where the issue is since it performs a test of the whole supplemental restraint system (SRS) checking for voltage drops across the entire system.
Happy Boxstering,
Pedro

Took me 4 trips to the dealer
 

to finally get mine right. Both seat belts were first. Then a TSB and finally a revised procedure for the TSB according to the tech. Once done right, no problems for 5+ years. The TSB is on my web site. https://sites.google.com/site/mikefocke2/airbagwarninglighttsb