Norcold works on AC not propane

I did remove the upper access panel to try to remove the interior baffle in the propane flu but it wouldn't come up and out, would wiggle but could not lit it up. The fins looked fine, no real dirt or nests. Cleaned the flu best as I could from the top and from the bottom with a stiff wire to remove carbon, but not really much came out the bottom. Kept the burner covered doing this. Blew off the propane burner orifice with a straw. Did a fuse continuity check on both fuses, both OK. It's very puzzling. Works great on AC, propane burner fires right up. Looks to be a good steady blue flame with just the lightest trace of orange in the middle. It's either not a hot enough flame or the heat transfer is not taking place as it should. Just got back from an extended trip to Yellowstone, other than this issue all went great. I know high altitude can affect some propane systems but now back to near sea level and still no cooling on propane. ??