So I've been having trouble on and off with my electrical system for a while now. I pulled in to my garage this morning and turned the engine off, but left the accessories on. all of a sudden, everything went out. Obviously the car wouldn't start. I checked the battery cables and they were tight, but just then the underhood light goes back on. I've had my dealer look at it, they tested the battery and said it was fine (new yellow top Optima) and all other electrical checked out fine. I do have my HIDs and my sub system running off my battery, is that the problem? any insights? Its happened about three times in the past 2 months.

 

Have you had rain as of late ?

I would check behind the cab fuse box for signs of water damage. Some have had similar problem with this, due to the GEM getting wet. Caused from the windshield not being sealed.

Just a quick first check

 

hmmm... it hadn't rained for a few days, but it is always dewy in the morning. where is the cab fuse box located. I'll check in the morning.

 

The access panel for it can be seen by your left knee in the anti submarine panel.

owners manual will have a picture and location description.

You want to look up behind the dash, along the firewall.