PATS Code 1:6 means you are losing electrical power in the cluster, and if gauges also go on and off that would confirm that
So you have a voltage issue
First thing would be to clean battery terminals and cable ends
Test battery with volt meter, don't care if its brand new or 10 years old, TEST IT
Key OFF and after battery has sat unused for at least 4 hours, longer is better
12.8volts is a new battery
12.5v is a 3 year old battery
12.3v is a 5/6 year old battery and time to shop for battery sale
12.2v or less is bad battery replace it <<<this would be the problem
Pull out, clean and test fuses 9, 10, and 33 in cab fuse box