I found another thread that was started in 2018 for the same issue and I see you posted there. So you've seen a user that changed a start or run relay in the TIPM and successfully restored his steering wheel heat function. He posted pics showing the relay location.
There's a newer post in that thread that identifies damaged connector wiring on a module under the driver's seat. It fixed his steering wheel heater problem, after repairing the wiring and then replacing an opened fuse. Have you inspected these connections?
Mine are now working, and the only thing changed is the weather. So, it must be temperature related. There are other threads that discuss it. It's cold outside, and now my heated seat and heated steering wheel can be activated. Next problem is trying to understand why they don't energize...
www.ramforum.com
This site may assist you in identifying what the connectors look like. Enter your truck details and search heater or steering.
http://connectors.dcctools.com/home.htm
This is an excerpt from a PDF manual for my truck indicating the fuse for the heated steering wheel. Another quick & easy check is to locate and inspect/test the fuse.
View attachment 514886
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