Hello XXXXXXXXX,
I know how frustrating an intermitten problem can be.I have worked for GM since 1971 & when a customer buys a new vehicle & you have an odd intermitten problem ,all they know is I want it fixed now.The best way to find a problem of this nature is to separate the different circuts from each other.Install a circuit breaker in each to eliminate each other.There will be a common splice in the harness.I must say that if it shorts out a circuit breaker (I am guessing it's 30 amp) I would look towards the power seats. This circuit draws more amps than any of the other you mentioned.
John
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Master Automotive Technician
ASE A1-A8 & L1 Master GM Tech 40 years experience