Thank you all for responding.
I agree, if you take the blower apart enough to get to the high temp. switch, then replace it. I do have a spare high limit switch, and I am in the process of replacing it. As FYI, cost for a Dometic PN 37022, the current day replacement, was $21.04 with tax and shipping. The prices are all over the map, just make sure it is an OEM supplied one.
From Doug's comments, it appears he has seen these switches fail before as they get older. Not sure if they fail open, stay stuck closed, how many years it takes, or run hours of the furnace to get to that point. It would be good to know.
On taking the time to test the furnace, if this was a charged job, time is money and the time spent with extra testing is hard to absorb or pass on to a customer. In my case, time is something under my control and cost is secondary, there is no waste. The knowledge learned from the testing, was worth it for me. I'm retired and restore water infected campers. I now know more now then I did before, and I know better for the next time.
Thanks again, grateful for all the responses/help.
John
