Aahhh...the plains of Arizona. I didn't even notice your location. Heat is definitely a killer. If it's 118F ambient, then it's even more under the hood . Now I see your dilemma .

 

After returning home from a trip on Sunday, I have been attempting to find the source of the drain on my batteries.

Recharged the batteries and they held the charge.
Eliminated the alternator as the source of the drain.
Unsuccessfully ran the check of all the fuses to find the fuse where the drain is coming from. Was working by myself and did the test with the drivers door open to make it convenient to pull a fuse and then reconnect the test lamp. With the door being open, the draw from the interior lamps created a draw that masked the real problem.
Reran the test with the door closed and removing Fuse # 15 from the incab fuse panel stopped the drain.

According to my owners manual that 5A fuse includes the Stop lamp switch, GEM Module, PCM, 4WABS Brake Shift Interlock, Cluster and PCM Keep Alive Memory.

Any ideas or suggestions on how to run checks to isolate the culprit? Does anyone know what cluster that refers to?

I have not removed the fuse panel to check for obvious signs of water or moisture on the GEM Module, but the first look above the panel did not show signs of water leakage from the windshield. Also ran my garden hose over the windshield and did not see any accumulation of water in the cab.

Would a problem with any of those electrical components throw any codes?


Glenn

 

Re-install the fuse and disconnect each part on your list individually and seperately until the light goes out.

That would not set a code.