Car electrcal system help

[tRiGgEr 5,000+ posts]

Here is the deal. My girls car dies on the freeway. Lights all flicker then turn off. Then the car shuts off. The battery dips to 3.8v when trying to start the car, so I get a red top and throw it in there. I start the car up and check the voltage 12.1v. Now I know it's supposed to be around 13.8v so I think the alt is bad. Take it in to AutoZone get it tested at 2 different locations. It's fine?! I put it back in and same problem 12.1v running. Thought it could be the voltage regulator but it's installed in the alt and it tested fine...

I'm stumped. Probably end up taking it in to a shop tomorrow.

Any Ideas?

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[Chevyaudio 5,000+ posts]

Where are you checking the voltage at? The battery, or somewhere else.

 

[JimJ 5,000+ posts]

Well, the problem is in the charging system...only a question of what...

I bet it's the regulator.

 

[tRiGgEr 5,000+ posts]

Where are you checking the voltage at? The battery, or somewhere else.

The battery. Re-connected the amp and checked the voltage back there, same chit. Normally the battery reads @ 13.7-13.9 volts while the car is on????????????????????????

This is really confusing me. Maybe my alt connection is corroded or somthin. I'll have to double check it.

 

[JimJ 5,000+ posts]

The battery should be reading in the 13.8-14 volt or higher range when the car is on. 12VDC won't support a float charge, so no wonder why you're going through batteries.

 

[Chevillac 5,000+ posts]

I had the same problem it turned out to be a bad connection at the battery. Every time there was a turn or speed up on the highway the car would flicker and usually turn off. After not figuring out the problem for a while the altenator went bad, ended up having to replace battery, connection and alt.

 

[tRiGgEr 5,000+ posts]

I'll double check all the connections to the battery and alt to check for corrosion. Looks like sears auto center will do a diagnostic check on the battery/starter/alt for 13 bucks. If it comes down to it, I'll drive on down there. If I make it:crap:

 

[Moe Lester 10+ year member]

did they just test it for output? or did they test it with a load on it

 

[tRiGgEr 5,000+ posts]

did they just test it for output? or did they test it with a load on it

???

They have testing equipment, Just hook up a belt, power and ground and start the motor up. 3 individual tests on it. Don't know the details of the test but all 3 passed.

As jack has said, I belive there might be a problem with the regulator on board the alt. And the AutoZone test may have not picked it up.

 

[tRiGgEr 5,000+ posts]

UPDATE

Just got back from sears. $13 dollars later it is the alternator/voltage regulator. Turns out AutoZone does not test with a load on the amp. Sears does It read -22amps and 11.98 volts. Well that sucks, So I'm going to buy an alt and install the sucka.

Thanks for the tips. I'm just glad it turned out to be an easy fix. Not some short that's unreachable.

 

[JimJ 5,000+ posts]

Negative current? That makes as much sense as Lemans...

But glad to hear it was something easy to fix.

 

[tRiGgEr 5,000+ posts]

Negative current? That makes as much sense as Lemans....

//content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif Should have seen my face when he told me that. I was like WTF are you serious...