• So to preface, I am in the process of sprucing up the 'ol gal (99 F-350 Super Duty, 2wd, 6 speed manual, four door, dually, Dana 80) to prepare her for her life's mission, and that is to be the foundation of my new home. I am in the process of selling my non-wheeled home and I will travel indefinitely with a truck camper on the back of this truck and a cargo trailer in tow with my three wheelers and Buell inside. If you're interested in seeing the big picture, check this out- The plan

I have battled on and off with an electrical draw on this truck for years. Over the last 3 years or so, it's not been so bad. There was a time when the windshield did leak and the draw was really bad then. The interior chime was going haywire as well as some lights and such. After having the windshield replaced and the leak fixed things improved. When I was driving the truck every day to work it wasn't an issue. Now the truck doesn't necessarily get driven every day anymore and it is time to tackle this draw.



I began today with hooking up my volt meter in series with the batteries and started tracing the draw. First from the under hood panel, then into the interior fuse panel. When I found the fuse that was correlated to the draw, I found the most likely culprit to be the GEM from doing research. I had never heard of this module before, but it makes sense that the GEM would be my problem. But then things get weird.



Rewind the clock about a month. My truck was in a million pieces in the driveway and had been apart for at lease two to three weeks, if not a month at that point. NO BATTERIES INSTALLED IN THIS TRUCK FOR WEEKS. Regardless of the fact that this truck had been dead dead for a month or so, there was a noise coming from the interior fuse panel. I said to myself "How could this be? There is no power coming into this panel. This truck hasn't had batteries in it for weeks." Regardless of that fact, it was still making a noise. I didn't mess with it at that time because I had bigger fish to fry.



Fast forward to today. Today was the day to investigate this draw. My batteries could certainly stand to be replaced at this point, but I'd like to fix this draw first. It killed the batteries in about three days of sitting. This morning I began testing and tracing as I said, I learned about the GEM, and I removed the GEM. At this point I had forgotten about the noise it had been making last month. I examined and cleaned the GEM, it looked fine, and I began to re-install it. As I hooked up the wiring harness to the back of the GEM, batteries disconnected, once the harness made contact the noise from the panel/GEM began again, with no battery power. How is this possible? I figure I'll swap out the GEM, I'm assuming the GEM is my problem, but how on earth could this module make noises for weeks at a time with no battery power whatsoever? I'm completely stumped here. Anyone heard of anything like this?



Here is a video I took of the noise. Please give it a listen.

 

That's trippy... do all of your electronic functions work door chime etc

 

Very weird. Are you replacing the GEM module? If you are, take the old one apart. Id like to see whats in that thing!

 

I have at least one more step before I replace the module. I actually did remove and inspect it and I did open it up. Everything looked fine but there was clear evidence that the module had seen water at one point, but that much I already knew.

I was on my way to checking the radio when I got sidetracked by the GEM making noise, and I forgot to go back and eliminate the radio from the equation. The radio is on that same circuit. Before I gamble on a GEM I'm going make sure the radio isn't the cause first.

 

Radio is not the problem. GEM seems very likely.

 

If you replace the gem module I would highly recommend caulking it closed with a water proof silicone to prevent any moisture from getting in the circuits. I also filled the connections with dielectric grease. Water contamination seems to be the major contributor why Gem modules fail.

 

I am having just about the same issue as you are. Battery disconnected test light on battery neg. to battery neg. cable test light is lit. Put volt meter on it and showing 11.25volts. go to fuse panel in cab and hear same noise as you posted. Start removing fuses and the second mini fuse on bottom from left noise stops and test light goes out. Fuse is for Instrument cluster. I will keep checking post to see how you make out or I will post if I figure it out.

 

I wouldn’t trust the alternator tester that the parts stores have. I have seen some test as bad but were perfectly fine. I have seen brand new units (not rebuilds) fail but we’re fine.

The battery light on the dash means the alternator isn’t outputting enough amps. Buy a new one and all will be well.

—Dave