2007 Sierra I Need Help

[Controller]

I have a 2007 GMC crew cab, 4x4 , 5.3 engine. This summer I would be driving and all of a sudded all the door locks start cycling, the AC would shut off, engine would lose power, all the gauges would go on and off, radio would lose its clock. I took it to the dealer and they said they found a loose wire on hte fuse block.

 

Two days later it does it again, and later that day it would not start, everything is dead just like the battery is not there, so I left the key on and openrd the hood, grabbed the negative cable and everything statred to work. Keep in mind this all happened just after my warranty expired. It's a complete pain to take it the dealer and have to take shuttles etc. and I'm mechanically inclined so I cleaned all the ground connections and it worked fine the rest of the summer.

 

Fast forward to this weekend, 16" snowfall, blizzard conditions. We are returning home from our god childs birthday party, I have it 4-Hi and it starts to lose its mind and 4 wheel drive fails and I get stuck with my 3 year old and my wife. I have found from past experiences with this thing that if I shut it off and let it sit a minute and re start it usually works. I shut it off and it won't start, same thing, just like the battery is not there. It finally did start and the 4 wd worked then and we got home, but I'm extremely upset with this truck. It only has 23,000 miles and has been babied. I need help.

 

I have noticed that sometime just before it acts up the voltage on the dash will drop to around 11.5 to 12 and the wipers move very slow. And again, if I shut it off and restart it is fine. Do I need to look at the alternator? The dealer will probably just keep replacing parts and I can't afford that kind of troubleshooting.

[xertechx]

I have a 2007 GMC crew cab, 4x4 , 5.3 engine. This summer I would be driving and all of a sudded all the door locks start cycling, the AC would shut off, engine would lose power, all the gauges would go on and off, radio would lose its clock. I took it to the dealer and they said they found a loose wire on hte fuse block.

 

Two days later it does it again, and later that day it would not start, everything is dead just like the battery is not there, so I left the key on and openrd the hood, grabbed the negative cable and everything statred to work. Keep in mind this all happened just after my warranty expired. It's a complete pain to take it the dealer and have to take shuttles etc. and I'm mechanically inclined so I cleaned all the ground connections and it worked fine the rest of the summer.

 

Fast forward to this weekend, 16" snowfall, blizzard conditions. We are returning home from our god childs birthday party, I have it 4-Hi and it starts to lose its mind and 4 wheel drive fails and I get stuck with my 3 year old and my wife. I have found from past experiences with this thing that if I shut it off and let it sit a minute and re start it usually works. I shut it off and it won't start, same thing, just like the battery is not there. It finally did start and the 4 wd worked then and we got home, but I'm extremely upset with this truck. It only has 23,000 miles and has been babied. I need help.

 

I have noticed that sometime just before it acts up the voltage on the dash will drop to around 11.5 to 12 and the wipers move very slow. And again, if I shut it off and restart it is fine. Do I need to look at the alternator? The dealer will probably just keep replacing parts and I can't afford that kind of troubleshooting.

 

I had this exact same problem with my 07 sierra, I just turned it in and got another one. The dealership could not figure it out but im betting its a BCM or something of that nature. Of course dont tell them this when you trade it in.

 

GET RID OF IT, it is not safe to have that truck! It happened to me on the freeway, it just shut off, nothing. My old lady said she would never ride in it again, so I traded it in that week and got the new 6.2

[xertechx]

I think I know why it does this. When it rained heavy out here I noticed water dripping out of my dome light. There was water on my dash as well. It looked like the windsheild wasnt properly sealed and thats what was causing it. Either way, this is a problem you dont want to deal with, I really suggest you consider getting out of that truck. They have great 0% apr deals and discounts on the new GMC trucks.

[ChevyTech77]

Two things,

 

1) Poor battery cable connections at the battery or main fuse (inline in the positive battery cable).

 

2) Excessive voltage drop across battery cables.

 

Both are covered under the same Preliminary Information document PIT4816C.

[Controller]

Two things,

 

1) Poor battery cable connections at the battery or main fuse (inline in the positive battery cable).

 

2) Excessive voltage drop across battery cables.

 

Both are covered under the same Preliminary Information document PIT4816C.

 

 

Thanks for the info, will check all the connections again

[ColoradoSkiCountry]

Had similar issues on my 07 as well, I traded her in for my 2500 without knowing fully what the issue was, the dealer was baffled. Truck was towed in once and when it came off the tow truck it was running just fine they tried but could not duplicate the problem. I got stuck with the tow bill.

[Controller]

I found this and it describes exactly what is happening.

 

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

 

Condition/Concern:

Some customer may experience one or all of the following concerns.

 

1) Intermittent No Crank or No Vehicle Power ( The customer may get the impression that the vehicle actually has a dead battery )

 

2) Volt gauge fluctuates, and seems to decrease when a high load accessory is turned on ie.. headlamps, wipers

 

3) IPC backlighting flickers or IPC goes blank

 

4) Diagnostic Code: B1325 set in several modules followed with a Dtc: C0900 set in the EBCM.

 

5) Radio clock resets

 

6) Intermittent Stall

 

7) Hvac temperature actuator defaults to hot

 

8) Door locks cycle

 

Recommendation/Instructions:

If you experience one or all of the following concerns and a cause for the concern can't be identified, please check the following items:

 

1) Remove the 175 amp Mega fuse and inspect for arcing, if any type of arcing is found replace the effected components.

 

2) When re-installing the 175 amp Mega fuse, torque fastners that attach the mega fuse to the positive cables to specification in SI.

 

2) Check the voltage drop reading on the positive and negative battery cables. The voltage drop should be performed with the fuel injectors disabled and while cranking the engine. The voltage drop should not exceed 200 Mv. If the voltage drop is above 200 Mv, replaced the effected cable.

 

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

 

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer forRead more at http://www.cadillacforums.com/forums/cadil...ack=kcplinkRead more at http://www.cadillacforums.com/forums/cadil...?ktrack=kcplink

[ColoradoSkiCountry]

[Z71-K9]

Had the same exact problem with my 07. Dealer replaced the megafuse thing and tried many other things to fix it. After many trips to the dealer I figured out the problem. When it would not start, if I grabbed the negative cable to make sure it was tight, I would get power back. Cable was tight. I would jiggle it about a 1/4 inch and power back on.

 

Dealer pulled the cable off and bench tested it. Found no problem. When I demonstrated the issue in the parking lot, he ordered my new cable. I have not had a problem since then.

 

Oh, mine was out of the 36,000 mile warranty. Dealer fixed it without cost.

[stefman722]

I have this problem with my 2009. Has done it several times. Unreal.

[Nick The Great]

I wonder if this solved the OP's issues?

 

I had this with my 2007 two winters ago. Mine would almost never start after I shut it off. I was able to wiggle the neg cable and it'd fire right up . . . for a while. 3 times at the dealer before anything helped. To this day, I still don't know what they did to fix it. I have my suspicions it was a bad connection where I could see/reach in my garage.