2008 duramax loses all electrical when trying to start

[motobean95]

Hi everyone. I have an 08 duramax. Sometimes when I go to start it I turn key and ALL power shuts down lights gauges everything. Then I cuss and get angry and a few minutes later they all come back on and the truck starts just fine. Not throwing a code at all. Batteries are brand new . any suggestions?
Thanks in advance

 

[juddski88]

Loose battery cable?

 

[Burn Down]

I was just messing with this on the 05', the exact same issue. Near as I can tell it was a loose connector at the at the tcm. This truck also had a BD Tap Shifter installed so I made sure these were clicked in place as well. Seems fine now and I can't move the harness around and make the power come and go.

 

[2004LB7]

Always check your battery connection first

 

[motobean95]

Battery cables are clean and tight I thought maybe a loose harness too but it kind of resets itself after a min or so. Almost like a relay but I lose all power not just one thing or another

 

[TheBac]

You should probably pull the cover off the underhood fuse box and check for evidence of rodent damage. I'd also check the main power lead integrity where it attaches in the box.

 

[1FastBrick]

Didn't the 07 and 08 have under hood fuse box connection issues in some cases causing an intermittent loss of power?

 

[motobean95]

Didn't the 07 and 08 have under hood fuse box connection issues in some cases causing an intermittent loss of power?

Anything more abut this????

It's weird cause a min or two later it comes right back to life on its own

 

[1FastBrick]

I remember a few people having issues that were tracked back to the connection under the fuse box.

See this thread. http://www.gminsidenews.com/forums/f31/silverado-electrical-nightmare-106736/

 

[Ron Nielson]

When the problem occurs, start shaking the battery wires, wires to the fuse box, wire to the starter. Something will show up. Try connecting a jumper cable from the battery neg to the engine block, or to the firewall. No question there is a circuit problem. Corrosion can be a real problem. Just a 5 ohm load can kill a circuit and corrosion can be a 5 ohm problem easily. Any green powered stuff around or under the fuse box? Look for broken or chewed wires.

 

[motobean95]

When the problem occurs, start shaking the battery wires, wires to the fuse box, wire to the starter. Something will show up. Try connecting a jumper cable from the battery neg to the engine block, or to the firewall. No question there is a circuit problem. Corrosion can be a real problem. Just a 5 ohm load can kill a circuit and corrosion can be a 5 ohm problem easily. Any green powered stuff around or under the fuse box? Look for broken or chewed wires.

I don't see an corrosion. and I've tried playing with all the wires but like I said it comes back to life by its self in a min or two. I've tried to MAKE it do it but it just randomly does it when starting the truck . is there any relay that would kill EVERYTHING and then resets? I know there are many relays for this or that but I lose ALL power. No door locks or dome lights nothing.

 

[2004LB7]

I'd look closely at the mega fuse(s) and related wiring

 

[1FastBrick]

Another Option could be the electrical part of the Ignition Starter Switch. I did one recently and their cheap and easy to do.

Vehicle would be dead. Left owner stranded in parking lot a few times. also stated it died at in intersection but restarted. Had it towed home 2 times. Always worked for me and could never get it to duplicate issue. After replacing the electrical part of the switch, The issue has not returned. I expected to find badly burnt or damaged contacts in side and that was not the case. At least it was fairly inexpensive part.

 

[JoshH]

Double check all your grounds too.

 

[motobean95]

I'd look closely at the mega fuse(s) and related wiring

Would the mega fuse reset itself after a min or two?

 

[motobean95]

Another Option could be the electrical part of the Ignition Starter Switch. I did one recently and their cheap and easy to do.

Vehicle would be dead. Left owner stranded in parking lot a few times. also stated it died at in intersection but restarted. Had it towed home 2 times. Always worked for me and could never get it to duplicate issue. After replacing the electrical part of the switch, The issue has not returned. I expected to find badly burnt or damaged contacts in side and that was not the case. At least it was fairly inexpensive part.

Would that such cause loss of electrical power to everything? INCLUDING dome lights and locks? WEIRD thing is it will reset after a min or two. NEVER dies while it's running .

 

[2004LB7]

Would the mega fuse reset itself after a min or two?

Im thinking of a loose or bad connection. Or perhaps a cracked fuse element that may make contact when cold but opens up when warm or something like that.

You need to measure voltage of the various lines and fuses when you have the problem so as to narrow down the location. Keep a meter or light probe ready in the truck so you can do instant checks. Follow the power to the fuse box from the batteries and see if any loose power