2022 Keystone Cougar 364BHL Furnace issue

[DBills]

Hello all, first time poster here.

I have a 2022 Keystone Cougar 364BHL and I’m having troubles diagnosing a problem with the furnace.

For background, I am a former Electronics technician for the Navy. While I’m not new to troubleshooting satellite communication systems and radar systems, I am fairly new to RV systems.

The furnace was working great until one morning it just wouldn’t kick on. I go to the iN·command touchpad and turn on the heat, but nothing happens.

We are connected to shore power, propane and batteries are good.

Upon opening the exterior furnace cover. The control board is giving me a (soft fault) for low airflow. One blink every 3 seconds. I’m assuming this is because the blower motor is not kicking on so it’s not closing the sail switch.

Things Iv done to troubleshoot so far.
- Iv checked the 15amp fuse and it’s good, even replaced it for piece of mind.
- Disconnected from shore power and batteries to “reset” systems.
- I jumped the blower motor with a 12v course and it kicks right on, so I know it’s not the blower motor.
- Iv checked incoming power at the fuse and leaving the fuse and have 13.65V, yet when I check the wire going to the furnace control board I’m only seeing 3.5V.

Any ideas or tips on where I should look or troubleshoot next would be greatly appreciated. Trying to troubleshoot and fix it myself before calling a mobile tech or taking it in to camping world for service (yikes).

Thanks all.

[chuckster57]

Welcome to the forum

If you can get to the 4 wires from the furnace try this:

Hook up 12VDC directly to the power leads. Then take the 2 blue wires and connect them. If the furnace operates you need to start looking at the supply voltage.