Battery or starter

BIGALLOYMAN

MEMBER
2003 CHEVROLET AVALANCHE
5.3L
V8
4WD
AUTOMATIC
280,510 MILES

When it is cold in the morning usually below forty degrees sometimes it cranks a little and then nothing like the battery is drained, but when I check the voltage on battery it is over thirteen volts but as soon as I hook up my jumper starter it starts right up. I have changed the cables to the battery to starter, to alternator and fuse box it still cranks slow some times it starts some time it does not. Then I jump it and it starts right up. So is it the battery not holding charge under load or the starter? It could be the original starter not sure. Thanks for your time.

3 Replies

CARADIODOC

MECHANIC
33,761 POSTS

Next time it does this, have a helper turn the ignition switch to "crank" while you measure the voltage on the smaller terminal on the starter solenoid. If you find close to twelve volts there, a somewhat common problem was the coil of wire inside the solenoid warps, then the plunger sticks. If the plunger does not move far enough, it will not turn on the high-current switch to run the starter motor.

If you do not find any voltage on that smaller wire, try starting it in "neutral". If that works, suspect the neutral safety switch/transmission range sensor.