What make of vehicle, and what is the 'problem'?
I'll tell my story - from quite a few years ago.
We planned a trip that took us out in the back blocks of New South Wales and into Queensand [Australia if your wondering!]
In a Ford sedan.
One secton of highway was a little rough - to put it mildly, and on the dash the "Air bag warning" light flickered on and off a few times.
Then a real wallop of a pot hole, and the light came on and stayed on.   120km from the nearest town with any chance of a Ford dealership.  O well - just got to keep going!
Finally got to outback town of Bourke. Ford mechanics there said we dont have the specialist diagnostic tool to sort out what the prolem is.  Good news is that if the air bag has not popped - it is not going to!  Put a bit of masking tape over the warning light if it is annoying you!
Long story short, travelled the rest of our planned trip and got home to central Victoria. 2500km!
Local Ford dealer - who has outlets in two towns 40km apart - said his diagnostic tool was in the other workshop.
Had to go to our regional city of Horsham, so rang the Ford guys there and explained the 'problem'.  They said "pop in and we'll have a look!"
Mechanic said he'd heard of similar problem.He shoved the drivers seat as far back as it would go, put his head down with the accellerator and brake pedals, feet up near the dome light!, and stuck his hand up between the lining panel and the metalwork.  His next words were "Ahah - got it!"
He said to turn the ignition on please.
The warning light lit for a second, and went out [ as it should!]
He explained that a multi pin connector had worked loose - thus the flickering light for a while, then constant light.
He said to go for a test drive and make sure it stayed off.
It did!  When I returned, I asked for my account - as I'd never dealt with them before. 
He said  "No charge!  put it down to experience!  And if it happens again I bet you can find the multi pin connector!"

Good old country service!
It did happen again in the few years we had the Ford, and he was right - I fixed it!