Hi Glen, it does sound like the heat is causing something to expand and lose connection. The first thing to check would be behind the dash where the connector connects to the instrument cluster. With the key off, disconnect the connector and see if anything seems out of place or damaged in any way.
If it looks good, get yourself some dielectric grease and put it on the connector pins. The connector is a 26-pin connector, so anything could be causing it to lose connection.
I attached a pic of the connector below. Keep in mind, this could also be the printed circuit board in the cluster itself.
Let me know what you find or if you have questions.
Take care,
Joe
See pic below.
Image (Click to make bigger)
Thursday, June 16th, 2022 AT 9:21 PM