Help troubleshooting heater

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Jan 28, 2019
Hey guys i did some searching but i haven't been able to find what i was looking for. What im looking for is a flow chart (or something similar) on what steps to take to troubleshoot heater issues. I have a 2010 Dutchmen TT, that i bought last year. The heater worked for a few time we took it out but then one day when i was towing it i kept hearing a fan running. After digging around i realized the HVAC fan was running all the time, i made sure the thermostat was in the lowest heat setting and the on/off switch was set to off.

They both were off and the fan was still running. Since i didnt have time to dig in i pulled the HVAC fuse and the fan stopped. After i got some time to go back to the TT i put the fuse in and instantly the fan would start running, i turned the heat on and it worked for about 30 mins and then no heat but a constant fan. I left it cause it was getting towards the end of the camping season and i decided to go look at it and now the fan doesnt run if the fuse is in or not, and no heat at all. Gas works in the hot water heater and the stove so i dont think its a supply issue but im lost when it comes to TT heaters. I can of course take it in to a shop but i thought maybe if there was a decent flow chart or if anyone had some ideas that would save me money would be awesome. Thanks in advance
Ask and ye shall receive:

Written by Gary the Wizard, a member here. Very straight forward guide. This in the site library. Just click on the tab above. There's a lot of good information there.
The furnace has its own 12v fuse and supply wire, separate from the thermostat.  Start by double-checking that fuse you pulled (use a meter, not eyeball) and also test for +12v right at the furnace.
Hey sorry everyone I didn?t have alerts turned on so I didn?t know anyone replied. Thank you for posting that. I tested voltage etc and everything seem to be good. Just no fan and no heat, on a whim I ordered a digital thermostat and replaced the old one and what do you it runs like a champ now. Weird cause that t-stat looked ok etc not sure what happen to it to cause it to run the fan all the time like that, but i have heat again! Even though it?s -2 at the moment she fired right up and I was able to control the fan. Best $19 I?ve ever spent!! Thanks again everyone
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