I have a 03 coupe 6mt. The car failed for state inspection for the airbag light no coming on temporarily on startup. I have aftermarket seats in the car without the resistor trick so it should be flashing. I tested if it was the module by unplugging it completely and seeing if it'll come on or flash like the fsm recommended but still nothing. Any advise would help.

 

Maybe the LED went bad on the gauge cluster?

 

Yeah that's my guess, bad instrument cluster probably but it could also be a bad diagnosis sensor unit (airbag computer)

I would disconnect the battery, reach under the passenger seat and unplug the yellow harness, plug the battery back in. Now drive down to an Autozone, Oreillys, or other parts house and have them scan your car. It SHOULD be throwing a code since you have the occupancy classification system on the seat unplugged. If it's tossing a code but you still don't have a dash light then it's probably a bad cluster.

If it's NOT tossing a code make sure their scanned can actually test for body codes (starts with a B####) and has protocol ISO 9141-2 which is what Nissan uses. It should be stamped on the case of the scanner somewhere.

If the scanner still doesn't read the body code go to another parts house and see if they can scan it, if it's STILL not finding the B code then it's probably the diagnosis sensor unit (airbag computer) is malfunctioning it sends the signal to the instrument cluster to turn on the light, even during the POST (power on self test) when you turn the key to ON. Without that signal from the diagnosis sensor unit that light WILL NOT turn on.

There are some fuses that supply power to the diagnosis sensor unit, it's all in the FSM section SRS - Supplemental Restraint System. Check the fuse, backprobe the sensor unit to make sure it's got power, if it has power it's probably a bad sensor unit.

 

Since these cars have known cluster issues I went ahead this morning and ordered a new one. So I'll find out in a couple days if it solves it

I forgot to mention in the post but I've tried a known working diagnosis unit still nothing. I've checked voltage at the unit it's for power but can't find a pin out for the cluster itself Thanks for the advice my buddy is meeting me after work to bring his shop scanner to check for codes.

 

What about your seatbelt indicator, that signal is also handled by the SRS diagnostic control module as well for the occupancy classification. If you have a seatbelt light on when you unplug the passenger seatbelt while sitting in the passenger seat, with the engine running, then you know the unit is at least functioning in some capacity. I can't remember for sure but you might actually have to be DRIVING for that light to turn on. If you have a 20lb dumbbell or a bag of sand, dogfood, etc that's heavy enough to trigger the switch you can test it by yourself.

It's two separate circuits from the diagnostic control unit to the instrument cluster though, one for the seatbelt warning light, one for the airbag light. Here's the wiring schematic for the seatbelt indicator and airbag light.

 

I'll check the wires out tonight, thanks for the schematics. I know the seatbelt indicator works.

 

The seatbelt indicator for the driver seat doesn't go through the occupancy classification system in the SRS computer since it's always assumed the car has a driver. So you can't test it at the driver seat, gotta be a passenger seatbelt test.