Fuse 39 2003

[Elvir93]

Hi,

My 2003 mustang convertible is starting to die again, after a day, sometimes sooner.
So fuse 39 is drawing significant power from car. I’ve changed the alternator and battery 3 times in the past 2 years, so there is definitely a drain. There is also a drain on my subwoofer fuse.

Anyways, seems like the biggest drain is fuse 39 or the “gem” fuse. I’m researched the function of it, and was wondering about how to solve this problem?

Thanks.

 

[wmburns]

One of the keys to solve this problem is to look at the INPUTS to the GEM. It seems possible to me there is some signal that is keeping the GEM awake (or causing it to wake back up). Think:

• Door ajar
• Driver's door key lock activation.
• interior lights
• trunk ajar
• remote door lock/unlock

Do you have an "advanced" ODB2 scanner? If you did it might make very short work of your problem. An advanced ODB2 scanner can talk to "other" modules besides the PCM. Here's some information on such an affordable ODB2 scanner.

ForScan ODB2 scanner w ELM327 USB

ForScan ODB2 scanner w ELM327 USB

While working on your car have you ever wanted: to find an ODB2 operational PID value (say fuel pressure or MAF)? How about graph a PID value over time? Or compare multiple PID's over time? Access a bi-directional PCM control such as test a...

www.stangnet.com

Suggest start by monitoring the GEM door open/close PID. Even better would be to data log all of the GEM inputs to a file. This would allow for viewing the inputs over time to see when they are changing.