the bulbs go in from the rear of the instrument cluster. it must be removed to get at them. there are 3 screws visable on the cluster (above the steering column) you must also pull out the radio bezel (2 screws above the heater/ac controls) and remove the driver's side lower dash trim panel to get at all the rest of the screws (6-8 as i remember) you'll also need to take the 2 screws out of the hood latch release to get the trim panel off (it then pulls off, held in place by 4 metal push clips). next remove the metal plate which you'll find under the trim panel (4 screws) then you need to unhook the PRNDL indicator wire (being careful not to break it) to get the cluster out. then there are several more screws securing the bottom ot the cluster housing. now you're ready to wrestle the cluster out enough to disconnect the 3 wire harnesses from the back and pull it out. the bulb locations are labeled on the back of the cluster and all holes have bulbs. there's probably several bulbs not being used on your truck, for options you don't have, so you can just switch an unused bulb for your air bag bulb. while your back there change the 6 cluster illumination bulbs (#168). figure on this taking several hours if it's the first time you're doing it. no special tools are required. if your PRNDL indicator didn't line up, now's the time to turn the thumb wheel that adjusts the pointer. reassemble in reverse order. have fun...
tips:
1. disconnect the battery before starting
2. set the parking brake so you can move shift lever out of you way
3. place a towel over the steering column to keep from damaging it
4. a 1/4 ratchet set is very helpful (sae sizes will work for all screws)