gas refrig not starting

Dometic fridges (at least) have a gas shut-off valve at the burner assembly. If it's shut off, obviously the fridge won't light. You might look for something like this. On mine, the valve looks rather like a knurled set screw and turns a quarter turn, and is hidden behind the added sheet metal put in with the recall work.

On mine I have a small gas flow valve in the outside refer panel. Over time I've had to adjust it to allow more gas to flow. That did it for me.

New generator control boards do have LED on them, that will flash a code.
Check if you have one of those.
If cleaning the burner is not helping, new board would be next suggestion.

sounds like rust flakes on the burner, when mine did it, i took off the inspection cover,, it looked clean, but would not fire up, vacuumed it out,, it worked , then stopped, vacumed again and worked. i think the heat worked some more lose.

Had a recurring problem with my '94 Flair that the fridge would not start because a tiny piece of carbon would bridge the gap between the ingiter points so it couldn't spark. Just open up the access panel and clear that gap and it was good to go.

I do have a much older rig but I find I need to blow out and clean the burner area if mine gives any problem lighting the gas.

Does the other propane appliances work?
Can you hear the ignitor clicking when you turn the refer on? Stand by the refer exterior access while helper turns the refer on to propane.
Does it work on 120 volts?
Check the burner area for debris around the burner.
Check the ignitor and flame sensor to make sure they are adjusted correctly.
Make and model of the refer?

When was the last time it worked on gas? Igniter works on 12v do you have 12v at the igniter?

Tried turning it off?

2012 prime time tracer dometic refrig. never had an issue with system lighting before