First no crank/start, now starts but gauges go out!

[Jvoles]

Hello, I have been racking my brain (and my friends brains) over this one for two days now. I have a newer body style '07 GMC 2500 HD.

Yesterday morning I went to start my truck and when I turned the key the dash would go out and no crank whatsoever. I had a friend come and jump me (assuming it was the battery) and still, nothing. Tested the battery and it was perfectly fine.

After leaving the battery disconnected for about an hour, I hooked it back up and turned the key and it started right up. "Great", I thought. When I put it in drive, all gauges dropped and radio went out, but still running. Turned it off, tried starting it again.....nothing.

Unhooked the battery again, cleaned all connections (assuming now that it was bad connection) hooked it back up and started it with no problems. Let it run for about a minute and gauges/radio went out again. Turned it off, started it right back up, but no gauges/radio.

We had a heavy rain yesterday before this happened, not sure if it has anything to do with it but it seems to me like something got wet and is slowly drying out enough to start but not keep the gauges and radio going.

Please help! I should note that this happened to me a year ago and my friend talked me into replacing the starter, then the ignition switch, then the engine block ground strap, and then finally a new battery and it ran fine until now. I can't remember if it rained heavy before that happened last year, but we have had plenty of heavy rain since then and I have had no problems until now.

I'm at a loss now, my friend suggested a new computer but I hate to guess with a $300+ part.

 

[98trck]

you cured the problem once you can do it again
that makes me think its not the computer
retrace your steps ( you probably did already)
but when you replaced those parts, did you do them al at once or one at a time, which one fixed the problem
my experience in the past when I have a problem like yours, unplug and plug in every major electrical connection, remove and install every single fuse
I just remembered the dealer replaced my positive battery cable when I had dash gauges were jumping and acting weird, they said the resistance in the cable was too high
mine is 2011,
my truck was still under warranty when it happened
PETE

 

[Jvoles]

Well, I replaced the alternator and it started right up and everything seemed fine, but after about 15 minutes the gauges/radio died again. I have tested every fuse, checked/cleaned every ground, I'm getting extremely frustrated now.

It seems that if I leave my battery unhooked for an hour or so, it will start up and the gauges will be fine for about 5 minutes before going dead. I can drive the truck, but it's a little difficult when I have no idea how fast I am going lol.

I do notice that the "Service 4 wheel drive" message pops up right when the gauges go out, so I am thinking it has something to do with that maybe? I unhooked the actuator, unplugged the fuse, makes no difference.

 

[winger870]

If you are worried about not knowing how fast you are going get a GPS it will show you your speed. I had to use my GPS for a few days when my speedometer stepper motor messed up. My speedo showed me I was going 60 kmh in park lol.

 

[oldfoggie]

search this forum and the internet, this type of problem is common to GM, you should find some solutions, on my 2009 GMC Z71, I had a similar problem, I replaced the starter, and it worked for awhile, then showed up again at random times, I finally removed the ground stud on the block, mine was located on front passenger side, I cleaned it with a wire brush, mine hasn't given a problem since. you might want to check the battery connections on the starter, I cleaned the connections on the old starter and put it back on, I also ran a ground strap from the fire wall back to this stud, it is located on the fire wall on driver's side. hope this helps, another thing that might of had something to do with it is: I THREATENED TO TRADE IT FOR A HONDA, it may of worked.

 

[oldfoggie]

search this forum and the internet, this type of problem is common to GM, you should find some solutions, on my 2009 GMC Z71, I had a similar problem, I replaced the starter, and it worked for awhile, then showed up again at random times, I finally removed the ground stud on the block, mine was located on front passenger side, I cleaned it with a wire brush, mine hasn't given a problem since. you might want to check the battery connections on the starter, I cleaned the connections on the old starter and put it back on, I also ran a ground strap from the fire wall back to this stud, it is located on the fire wall on driver's side. hope this helps, another thing that might of had something to do with it is: I THREATENED TO TRADE IT FOR A HONDA, it may of worked.

UPDATE:
It is September 2018, I have not had any problems with my Z71 other than rust since I cleaned the ground stud