04 1/2 ton underhood fuse box issues - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Marv D · 05-09-2015, 11:23 AM

Will try to make this short.. My 02 4x4 went to the shop friday acting like a broken battery post (12v until you hit the key then 2v),, But the battery is fine, the cables are clean, as are terminals, bla bla,, Put a meter on teh battery when turning the switch and the battery shows 12.7 with only a slight drop,,,, but no start and everything goes dead inside. Headlights stay bright,, all power windows and everything acts like a good fresh battery.

I checked the power lugs under the cover of the fuse box,, full 12v there,, I gave up and towed it to the shop. A day of tracing the problem expecting the ignition switch,,, and he found a melted terminal under the bottom side of the (underhood) fuse center. Apparently the cabin gets power to the ignition switch from TWO legs,,, one of them had overheated and melted the fuseblock.

The question here is,,,

Has anyone had any issues like this. The only thing I can think of is we have multiple electronics we have to charge batteries for and use a small inverter plugged into the indash lighter / charger ports. The wire has never felt hot to the inverter or the charger) and the batteries are similar to 4 AA. Otherwise I'm at a loss.

GM wiring and electronics really takes a beating here in the Az desert at 100°+ all summer but DAMN they sure seem to be with NO durability in mind any more.

BrowningGuy88 · 06-10-2015, 11:00 AM

Funny you should post this...

My 2004 RCSB 4.3L Auto has been acting similarly. Mine is erratic which is the biggest problem. For instance, Sunday two weeks ago I drove it around town and towed my mower a couple times during the week - all was well with it. Then last Sunday (a week later) I turn the key and it will turn over strong but won't crank. All the lights work, the radio works, etc. so I chalk it up to a low battery and try to jump it off - same thing happens! Go ahead and drive my work car to run errands and when I get back home I decide to work on the truck - turn the key and it rolls over twice and fires off. It ran fine the rest of the week.

It is almost like I have something draining my battery to just below the magical 12V at times, but then on the same day with no charging it cranks fine. I have checked all the fluids, pulled fuses and verified they are good, and checked power cable lugs torque. I am at a loss on this one.

I really need to get it straightened out though because it is my back-up DD and my car is nearing 300k miles so I imagine I will be needing the truck anytime...

05-09-2015, 11:23 AM	#1
Marv D Registered Truck Offender Join Date: May 2008 Location: hells training ground (aka Ariz) Posts: 3,118	04 1/2 ton underhood fuse box issues Will try to make this short.. My 02 4x4 went to the shop friday acting like a broken battery post (12v until you hit the key then 2v),, But the battery is fine, the cables are clean, as are terminals, bla bla,, Put a meter on teh battery when turning the switch and the battery shows 12.7 with only a slight drop,,,, but no start and everything goes dead inside. Headlights stay bright,, all power windows and everything acts like a good fresh battery. I checked the power lugs under the cover of the fuse box,, full 12v there,, I gave up and towed it to the shop. A day of tracing the problem expecting the ignition switch,,, and he found a melted terminal under the bottom side of the (underhood) fuse center. Apparently the cabin gets power to the ignition switch from TWO legs,,, one of them had overheated and melted the fuseblock. The question here is,,, Has anyone had any issues like this. The only thing I can think of is we have multiple electronics we have to charge batteries for and use a small inverter plugged into the indash lighter / charger ports. The wire has never felt hot to the inverter or the charger) and the batteries are similar to 4 AA. Otherwise I'm at a loss. GM wiring and electronics really takes a beating here in the Az desert at 100°+ all summer but DAMN they sure seem to be with NO durability in mind any more. __________________ Still playin with trucks, even at my age! When you're dead, it's only a problem for the people around you, because you don't know you're dead. .....It's kinda the same when your STUPID. I just did my taxes and reviewed my SS statement. Thanks to the current administration it looks like I will only have to work till noon on the day of my funeral.

06-10-2015, 11:00 AM	#2
BrowningGuy88 Registered User Join Date: May 2015 Location: AL Posts: 8	Re: 04 1/2 ton underhood fuse box issues Funny you should post this... My 2004 RCSB 4.3L Auto has been acting similarly. Mine is erratic which is the biggest problem. For instance, Sunday two weeks ago I drove it around town and towed my mower a couple times during the week - all was well with it. Then last Sunday (a week later) I turn the key and it will turn over strong but won't crank. All the lights work, the radio works, etc. so I chalk it up to a low battery and try to jump it off - same thing happens! Go ahead and drive my work car to run errands and when I get back home I decide to work on the truck - turn the key and it rolls over twice and fires off. It ran fine the rest of the week. It is almost like I have something draining my battery to just below the magical 12V at times, but then on the same day with no charging it cranks fine. I have checked all the fluids, pulled fuses and verified they are good, and checked power cable lugs torque. I am at a loss on this one. I really need to get it straightened out though because it is my back-up DD and my car is nearing 300k miles so I imagine I will be needing the truck anytime...



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