Propane heater troubleshooting?

[bascom1968]

We have a 1977FC31 that we love. Just back from a trip from Tulsa area
to Padre Island and back without a hiccup. We did have an issue with
the heat though.

Can anyone help?

Our heater in the front area works great, the bedroom unit blows air
when you turn on the thermostat,but no heat, the kitchen unit does not
do anything. Where do you start troubleshooting? The tank has propane,
the range works fine as does the front heat. The bedroom unit is under
the bed and I am not sure where the kitchen unit is as there are
several registers but nothing happens with any of them.