I have a 2000 flagstaff 176ed I recently picked up. It was in rough shape but with a few repairs it should get me through the summer or maybe a few summers. The issue in having is with the propane heater. It's a dd-17dsi and it worked fine when I tested it at my parents place. But after a 5 hour drive home it refuses to stay lit. The fan cycles on, the sail switch closes, the valve opens, the igniter sparks and I get a nice blue flame, but after 5-6 seconds it closes the valve and goes out. It does this 3 tribes then goes to lockout. I tested it on 120v power and I have a brand new converter and battery installed properly. I'm thinking there's a flame sensor somewhere but I don't know where it is. I checked the wiring diagrams and troubleshooting steps from the manual but it all looks good and still having this issue. Anyone able to help at all?