Furnace blowing cold air only

ok the blower continues to run but air is not hot

ok so the Sail switch was good
all clean and connection good
I put everything back together and cranked the thermo to 90F
its 20C here today

Take the four screws out marked with red arrows, this should remove protective cover.
Sail switch is behind the top right red arrow.
The circuit breaker protects the motor. Left side
The time delay relay delays the fan shut down for a cooling off period, right side object

I removed the 2 screws and there is nothing coming out of it so I believe that is a Relay
How do I access the Sail switch?

ok there is only 2 black boxes
1 on the left is Breaker with littlte push button
and 1 black rectangular box on the right at top
has 4 wires going into it and 2 screws holding in
Do I remove those screws to clean it or do I remove the 4 screws holding in the face of the blower?

No, it is on top of the blower housing. Look on top of the larger blower housing, between it and the top of the furnace housing on the right side. It is very small rectangular object. About 3/8 thick and 3/4 inch square with metal arm sticking out to the left into blower housing.
Item 48 on page 37
Parts breakdown

Ok thanks.
1) the thermostat does call for heat
2) the Blower does tutn on and blows cold air
3) motor does run
4) I do not hear any ignition noises at all >> blower still running
5) I waited maybe 10 minutes >> no warmth >> maybe I should wait longer?

I will fire it back up now and see what happens
I'll post back

First understand how a RV furnace works which is very different from a residential furnace:
1. Thermostat calls for heat
2. Blower motor turns on and blows cold air out of the vents
3. Blower motor continues to run for several minutes
4. Burner ignites and gradually warms the heat exchanger
5. Air blowing out the vents gradually warms as the heat exchanger warms
6. Thermostat is satisfied and turns off the burner
7. Heat exchanger gradually cools
8. Air blowing out the vents gradually cools as the heat exchanger cools
9. Blower motor shuts off

It may take several cycles of the blower motor coming on and the burner trying to ignite until it finally ignites if the RV has been sitting or you changed a propane tank. If the burner does not ignite after a very short time, then the blower motor will turn off.

If you turn down the thermostat before the burner ignition cycle starts, the blower motor will turn off.

There are several safety devices built into the furnace that can prevent the burner from igniting. They can be doing their job correctly, or they could be faulty.

So is the SAIL switch under the Breaker on the left?