Electrical Problems

[DisplacedBuckeye]

I have been dealing with a few electrical issues since I bought my 2008 Denali. It's all intermittent, which makes me think I have a bad ground I can't find. Here are a few things going on:

• Intermittent message for StabiliTrak and traction control being off
• TPMS gives me an error to check tire pressure and the pressure fluctuates between 1 and 99 psi
• Remote start sometimes will not work
• When driving, sometimes I will lose power to all electrical in the truck, but there is no noticeable loss in engine power. When I stop it won't turn on at all like it's dead. If I wait about 20 minutes, it fires right up like nothing happened.
• Yesterday, driving on the highway, the loss of electrical happened and the truck was having trouble finding gears and was downshifting.

All of this happens intermittently, and infrequently. Most of the time, the truck drives just fine, but it's becoming a hassle.

 

[dreww2001]

I've had tons of electrical issues with mine it may be just a car that was possessed from day one or a design issue that was worked out I had gauge cluster go out, radio stop working, heat seats stop working, memory seat can be funny some times and the tire system too

 

[DisplacedBuckeye]

So after checking into this a little further, I think it's most likely the same issue others had with the negative battery cable. Does anyone know a part number on that or where to get a better aftermarket option? My tools are all being shipped across the country right now, so I'm limited on what I can do.

 

[07 Denali Xl]

So after checking into this a little further, I think it's most likely the same issue others had with the negative battery cable. Does anyone know a part number on that or where to get a better aftermarket option? My tools are all being shipped across the country right now, so I'm limited on what I can do.

So what did you figure out? This is similar to my 07 Denali Xl issue. Mine is dead right now.

So after checking into this a little further, I think it's most likely the same issue others had with the negative battery cable. Does anyone know a part number on that or where to get a better aftermarket option? My tools are all being shipped across the country right now, so I'm limited on what I can do.

Did you figure this out?

 

[DisplacedBuckeye]

So what did you figure out? This is similar to my 07 Denali Xl issue. Mine is dead right now.

Did you figure this out?

I haven't, but I'm almost positive it's the negative battery cable. I'm in temp corporate housing right now, so I just parked it and I'm driving my car for now. I'll let you know when I get a chance to look. I'm planning on just putting in a 4 AWG wire with new connectors.

 

[DisplacedBuckeye]

Does anyone know the following:

• How long is the ground cable?
• What size are the connectors?
• What size wrench is needed to remove the cable?

I'm going to try changing it without someone giving me a hassle, but don't have any of my tools yet.

 

[DisplacedBuckeye]

OK, so the Denali has been fine for the last week, so I decided to drive it to work. It drove fine, no issues until I was about 2 miles from home on the highway. I got a "Service Charging System Warning" so I tried to make it to the next exit. Before I made it, the electrical completely died and it wouldn't shift. About 30 seconds later, on the exit ramp, it completely died and wouldn't do anything.

A buddy came out with a pack and we got it started using that, but as soon as he disconnected it, the truck died. We hooked it up enough to get it off the ramp and into a parking lot, but it's sitting now with the same issue. I'm thinking it might be the alternator, and now battery. Not sure if the ground was ever an issue, or if it caused the issue.

I'll be going back out today after work to check everything out. Anything I should check or look for before throwing in a new battery/alternator?

 

[mizzouguy]

Battery was fine before or it wouldnt restart after it sat. Likely its just dead now from not getting a charge. Put it on a charger and it'll run off the battery until it dies again. While its running I'd bet your voltage is less than 12. Alternator is definitely either bad now, or truck has a bad connection somewhere not allowing it to recharge properly. Check positive from alt to battery for corrosion and tightness. This wire also contains a fusible link internally, or at least the older ones did. Can check for continuity between both ends of cable. Then check ground wire for any issues. The main one from battery to wherever it goes. There is also a ground strap that goes from the post just below the windshield to the rear of the engine that has a habit of getting loose and causing issues. I bet something just went from loose (intermittent issues) to very loose. I hope this helps.

 

[DisplacedBuckeye]

Awesome, thanks for the reply.

The battery was working with zero issues other than the gremlins earlier, but I've never had to jump it or charge it. I'm going to grab the battery out of my other truck tonight and see what it does. I'll check all of your suggestions.

Thanks again.

 

[Brian Wilson]

As for replacing the cables, just go ahead and do the big 3. buy some welding cable in 0 Guage and some solder on connectors. I ran a few extra ground straps as well. this will help alittle in all your electronics even if you don't realize it right away. and it is cheap future protection. as for your other issues, I don't think they are all related to just 1 problem but a few small problems. definitely test the alternator and charge your battery. definitely do a continuity test on your cables. check your starter solenoid to see if it is bad. gm decided not to put a heat sheild on them for the nnbs trucks and they get very hot. mine was semi melted but worked occasionally. the remote start will not work if the CEL is on. the stabilitrack and tire pressure messages sound like a bad wheel hub to me. when mine went out the tpms went crazy right before the hub falied. it didn't make any noise prior to failing. none of the testing requires any money whatsoever if you have a good multimeter. if you need help just ask here.

 

[DisplacedBuckeye]

Thanks Brian.

I'm stopping by a friend's house tonight to borrow his multimeter, so I'll be able to test all of that out. It's not fun dealing with this while my tools are in the mover's warehouse. I'll probably end up parking it until I get my tools unpacked.

Question about your hub. Did you get those messages before your hub went out? I'll get those once in awhile, and it's almost always close to the issue with it losing power, then the messages go away and everything works fine.

 

[Brian Wilson]

I got the tire pressure message first. then the stabilitrack messages came right before my hub was too bad for me to drive. I jacked the car up to check for a bad hub after the stabilitrack message but I didn't try hard enough to move the wheel. these factory 20 inch rims and tires are heavy. I did the push pull test but I didn't use enough force as I'm used to working on small cars with factory small wheels. it was less than a week after the stabilitrack message that my car made a huge grinding sound pulling into a parking lot. This sound repeated every time I made a turn. I also noticed reduced gas mileage. by the time I realized I had a bad hub, it was bad enough I was not comfortable driving it. and I have been working on cars for a living for a very long time. I never had one fail quite like this. I'm not saying yours is bad, but I have a feeling it is. find out which tire is giving you an crazy signal. due to rotating tires, your car might say it's the right rear when it's really the left front. to test you could lower pressure in one tire and check the guages in your dash when you find the crazy tire signal, you should check that hub. and don't be afraid to manhandl that ******.

 

[DisplacedBuckeye]

OK, I appreciate it. I'll check everything out. It might get pushed to after we close on our house and I get setup in my garage.

 

[DisplacedBuckeye]

Ok, dropped the red top from my truck in it and it fired right up. Drove it home with everything off including lights. Battery light on and same message to service the charging system. Looks like a new alternator and cable upgrade when I can get it into a garage. I'll test everything out this weekend when I get some time to be sure.

 

[Brian Wilson]

Remember, the battery is meant to handle quite alot of amp hours are important as long as you aren't running a winch or crazy stereo. don't assume your battery is good because of 10 minutes run time or assume your alternator is bad after 30 minutes of run time. you can easily test each individually

 

[DisplacedBuckeye]

I took a few measurements of the alternator and battery:

Battery (not running): 11.90V
Battery (running): 11.57V
Alternator: 11.83V

I didn't check any of the ground because I'm not supposed to "work on" my car in the parking lot here. Anything specifically I should check?

 

[mizzouguy]

Alternator output is too low. Could still be a bad ground but my money is on voltage regulator and alt needs replaced.

 

[Brian Wilson]

Did you unplug the battery to test the alternator while running?

 

[DisplacedBuckeye]

I'm getting 0.6 ohms testing the ground from the battery to the engine block.

I didn't unplug the battery. I thought that was a bad thing on newer vehicles? Is that OK to do on ours?

 

[mizzouguy]

Pretty sure the truck will die if you unhook the battery while its running...idk.