Im new and I need help. I have a 2003 silverado 1500 ext. cab v6 auto. I bought it last Monday knowing it had problems. It also had a front end collission a while back that was minor I am told. It has 32000 miles and was a grocery getter for Gramma.
Here is what is going on.
When driving, the volt guage drops from around 13 to 9 10 or 11 volts. The ac blower slows down, lights dim, And on one accassion cut of when idleing. The voltage is going up and down. It doesnt matter if I am parked or going 40. It does happen a little more often when getting out of the driveway.Yesterday it didnt do it at all. Today it is doing it constantly. Also, the temerature guage works when it wants to. Today, I put a new alternator with voltage regulator on and it didnt change anything.I am aware of a recall for the cluster and have scheduled to have that replaced.
What is wrong? Short? Loose wires? Help!

 

Did ya check your positive wire connection goin from the altenator to the block?

 

I started looking for shorted or loose wires. I found the ground wire from the firewall to the block loose. YE HA!!!!!!!!!!!!!!!!!!!!!!!! I couldnt get to the bolt so I ran a new wire to a different location on the block. Thanks!!!! It is fixed. Except for the cluster. That should be taken care of under recall. By the way, the ac was overcharged to 500 psi on high side and would blow out refrigerant when you reved up the engine. Im starting to se a pattern of poor workmanship on the collission repairs.

 

I've had a '07 and I have a '09 now. The voltmeter on the dash fluctuates on both and it is described as normal in the owner's manual. They say it has something to do with maintaining the battery. It always comes back to "normal" and I haven't had any starting problems. I have not actually measured the voltage across the battery when it drops down but the dash meter looks like it is down around 13v or the battery voltage.

If your works like mine, when the alternator cuts back on the charge, the battery should hold up to run the lights, fan, etc. If you have a weak battery, that could be your problem. I would take the battery to Autozone or someplace like that and have it tested. Otherwise, it sounds like a loose wire. While it's in trouble, move the harness around and have someone watch the meter for you. If it is a loose wire, you should be able to make and break the connection and find the loose wire. Good luck.

 

Your fix beat my reply. Good work!!