Will not start without a jump?

Tiny
TONYG129
  • MEMBER
  • 1997 CHEVROLET BLAZER
  • 150,000 MILES
My blazer will not start without a jump I have replaced the battery and alternator. I have checked all fuses for shorts and drains and found nothing. When I have the truck off the battery is testing at just under 12 volts. When I turn the key to start it the battery drops to about 5 volts. If I hook up jumper cables it starts instantly. Could it be the starter or starter cellunoid?
Wednesday, October 12th, 2011 AT 4:34 PM

1 Reply

Tiny
SQM
  • MECHANIC
  • 6,383 POSTS
Hello,

If the battery voltage drops that fast then it is likely has a bad cell and is defective.
As you are able to jump start it and it runs fine the starter or the solenoid is not the issue. If it was the starter it would not have started regardless of jump start or not.

Perform a load test on the battery. This can determine if the battery is faulty.

You might these articles helpful:

https://www.2carpros.com/articles/car-battery-load-test
https://www.2carpros.com/articles/symptoms-of-a-bad-car-battery

Please let me know of any questions.
Thank you.
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Tuesday, August 31st, 2021 AT 12:03 PM

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