I'm driving my 1999 blazer today...i notice battery light on the dash is on. Then I notice the volts read low around 10ish maybe ...as i'm driving i can see my volts gauge dropping...gets into the red, i lose dash lights, speedometer, tach, fuel guage. Vehicle still running but starting to notice some hesitation as i got closer to home...I made it home just barely

Pulled out alternator to have it tested, it tested fine...brought back home, put it back in.
Took battery in, it tested low, bought new battery, put it in...still same issue...battery light stays on, on dash. I don't want to drain the new battery, so i'm not going to drive it around.

No other signs of trouble like this before today.

I'm going out to clean battery terminals now...

Ideas?

Check the alternator charging on the truck.
Go over and clean all battery cable ends.
Then check all grounds and power from battery to fuse box and ign switch.
All check all fuse and fuse links.

MT-2005, thanks for the reply...

Question though, how do I check the alternator charging on the truck?

Are you talking about testing how many amps or volts the alternator is putting out while on the truck?

MT-2005, thanks for the reply...

Question though, how do I check the alternator charging on the truck?

Are you talking about testing how many amps or volts the alternator is putting out while on the truck?


Both should be checked.

If you have a good volt meter look for 14 or more volts at battery terminals with engine running.
With everything tunred on you should be running around 14 volts with the engine at 2K rpm.

To check amps you will need a amp meter.
But if voltage is good usually amps ae ok.
Post back voltage reeading.

Checked voltage...with car running at 2000 RPM's

12.08 on back of alternator
12.09 on battery

That's just battery, clearly I was not getting any juice from the alternator. Took it in to have it re-tested, I took it to O'Reilys this time. They said it was bad! Then took it back over to Advance Auto Parts, they tested again, and said it was bad this time??...and since I had a lifetime warranty on it, they just replaced it for free!

Everything is back to working as it should!

Thanks for pointers MT-2005.

Checked voltage...with car running at 2000 RPM's

12.08 on back of alternator
12.09 on battery

That's just battery, clearly I was not getting any juice from the alternator. Took it in to have it re-tested, I took it to O'Reilys this time. They said it was bad! Then took it back over to Advance Auto Parts, they tested again, and said it was bad this time??...and since I had a lifetime warranty on it, they just replaced it for free!

Everything is back to working as it should!

Thanks for pointers MT-2005.


You are welcome and thanks for posting back how it went.
Glad you got it fixed.