May I make a suggestion that will work for most Electronic problems that are temperature related.

Buy a can of Cold Spray as used in Electronic test & repair.

It's used for locating thermal intermittent electronic component problem, PCB cracks, and cold (dry) solder joints.

If you, one at a time, use the spray on the suspect components it will allow you to isolate the problem item by cooling it down to it's starting temperature.

It is available from nearly every Electronic Hobby shop's and costs very little.

Get a big can as when you think you have found the item you can cycle it a few times to be really sure.
Also when electronic components are inside a metal case you need to reapply a few times in sucession as it will take a while to "Sink" through the casing.

Have used this technique for many years and found it foolproof.

Regards

Mike