Bad alternator?

[GangstaCowboy]

Bad alternator? Intermittent power loss at start up,not starting.

Hello-
My 2006 tahoe died about a week ago. We jumped it and drove home so I took the battery in to test at Autozone and they said it was bad. Installed new battery and ran like a champ. Today the tahoe died again, but this time a jump only got the car running for like 2 seconds. Sounds like the alternator is bad to me. I am going to take the alternator up to autozone to test. Any other suggestions? I noticed before I replaced the battery the first time that the lights would flicker at night inside the cab and the head lights would dim a little bit at random times.

 

[erikrichard]

What did the dash board volts gauge read on your way back home after getting the jump start? A battery that is discharged or close to it cannot be tested accurately, so auto zone's determination that the battery was done is in question. You could have a drain on the battery running it down, but that wouldn't explain why the truck won't run after it starts - again, you need to check the volts while running with a multimeter or just look at the gauge on the dash.

 

[GangstaCowboy]

Thanks. Ill check that tonight. We called to get it towed and tried starting it one more time and it started fine. Voltage on the dash was right under 14.

 

[GangstaCowboy]

I have never removed the belt on my Chevy vechicles. When I did this on other cars there was a belt tensioner that I could loosen. I don't seem to see one. How do I get the belt loose on this Tahoe?

 

[electro]

By turning the tensioner.

It is the left upper most pulley.

 

[DCT]

I recommend a multimeter, but your gauge is ahowing 14V. For another quick check of the alternator without removing it from the truck, get the engine running (if you can) and disconnect the battery. If alternator is bad, the engine will shut off.

I have friends who work at those parts chain stores. Every damn battery and alternator "fails".

 

[GangstaCowboy]

Thanks. I will try disconnecting the battery when I get hom to make sure. IF the car stays running is there anything else I can check? I suppose the alternator could be "failing" and that is why it runs the battery down. or there could be a drain on the battery but I wouldn't even begin to know where that would be. There are no aftermarket parts on this and I have never tinkered with wiring on it.

 

[PwtrSS_OakCliff]

On my Yukon it told me on the DIC that its not charging. Sometimes it charged and sometimes it didn't. I'm surprised your battery red light didn't come on. Make sure you take out corrosion and also check your cables and make sure they are not cut or melted also. GL

 

[GangstaCowboy]

so I disconnected my battery and the car stayed on. The voltage meter on the stayed above 14 but the lights flickered a lot. Is that normal.

 

[donut slayer]

Yes. Its normal. You need a multi-meter. Take a voltage reading before startup then after. Should be 12.6 or so off and above 14 idleing.

 

[erikrichard]

I don't think lights flickering is normal, mine don't. If the volts read about 14 when idling and stay that way when driving it doesn't sound like the alternator. Be more specific when you say the Tahoe "died" - was it totally dead as in no dome light? did the starter turn slowly or not at all? it was running then died, or it wouldn't start after sitting? for how long?
Hard to help with so much info missing.

 

[GangstaCowboy]

Thanks for the help. So the Tahoe would not start again after replacing the alternator. I measured the voltage and it is at 14 when idling. The starting problem is intermittent. I was just at the store and I turned the key and the card was completely dead. No power what so ever. I tried about 10 times to start and nothing. I got out tried the remote lock and it was dead. So I got back into the card and it started up fine, power was normal except the radio clock was reset but not the stations. Could the starter failing cause there to be no power like that?

 

[erikrichard]

Don't just start replacing parts on a whim. Buy a multimeter, that would have saved you from the cost of an alternator you didn't need. It does not sound like the starter, because everything else is dead too - if it were the starter, why would the locks and lights have no power? Best bet is a bad connection to the battery. I'd say it could be an ignition switch problem except the locks normally work without the ignition turned on. It could possibly be a computer problem.

 

[GangstaCowboy]

Would a bad switch cause no power for everything? It's almost like the battery loses connection. IO tracted he power wires as far I could but didnt find any loose connections

---------- Post added at 02:15 PM ---------- Previous post was at 12:35 PM ----------

Can anyone tell me where the ignition switch is located?

 

[ScottyBoy]

Check your battery cables, and not just the ends where they connect to the battery. Loose, and/or corroded connections can cause what you are experiencing. Even if the ends look fine, you can have corrosion inside the cable causing resistance.

 

[GangstaCowboy]

Cables look good, there is zero corrosion on them or by the connections.

 

[ScottyBoy]

Cables look good, there is zero corrosion on them or by the connections.

Did you check where the ground cable bolts to the engine and frame? And did you check where the positive bolts to the starter? Either of those can be loose or corroded.. Don't just look, physically wiggle it to see if its loose at all.

 

[erikrichard]

With truck off open hood and start wiggling and pulling on the cables going to the battery and wherever they lead to - see if you can get the problem to happen. With the door open and key in the ignition the chiming will stop if you've found the issue.
Typically what you have is a power wire from the alt to the battery, the battery directly to the starter and another positive wire to an under hood fuse block - this wire may be corroded or partially broken. You may also have a bad ground, look around for that using the same process of wiggling and pulling on wires with the door chime going.
That's what I'd do anyway.

 

[GangstaCowboy]

Thanks. I'll give that a shot in the morning.

 

[GangstaCowboy]

Thanks for all the tips. I went out this morning and had my wife sit in the driver seat with the door open and key in the ignition. Sure enough once I started shaking the ground cable the lights flickered or went out. Looks like the part of the ground wire to the chassis was loose and dirty. I cut the end and put on a new connector and really crank all the connectors down. Once that was complete I wiggled everything pretty vigorously and the lights stayed on and no interruption in the door chime. Hopefully this solves the intermittent problem power problem. Thanks for the help.