Electrical/starting problem

[Downey]

Well my truck had a hard start about 2 weeks ago. It just cranked slow then started. So I figured the batteries were low. I started monitoring voltage. Truck running was 13.7-14v. So alternator is charging. Well Friday morning I went to take truck to work and all it would do is click. So took other truck to work. At lunch jumped the truck and it cranked slow but started. Let it run for about 20-30 min and took it to work. Checked battlers with a meter when i got to work and both around 12.7v with truck off. Check hpo when cranking and making around 1300 lbs so no leak. Hooked up snap on scan tool to check ficm voltage when cranking. While have just the key on and setting up scan tool the truck voltage just dropped. Dash lights went dem and when cranked it just clicked. Scan tool said 7v.

Went and had batteries tested because they are under warranty and they are fine.

What can be causing such a draw that it kills the batters so fast the truck won't start? Starter? Alternator?

 

[6.0 Tech]

Check your cables for corrosion inside the covering, possibly a starter as well. With it cranking slow while being jumped, sounds like more than a battery. And if the batteries pass a test, and are at 12+ v prior to cranking, they are probably not the issue.

 

[Downey]

Yea it cranked slow while jumping too going to replace starter today. Going to check wires with meter today too to see what I get.

 

[co04cobra]

Who or where were the batteries checked?

We have had to replace several batteries that "passed" a autozone, or the like, battery test.


Starter is a very likely culprit too.

 

[Downey]

Advanced checked them because that's where they are warrantied. Was hoping it would be batteries so I could fix it for free.

 

[co04cobra]

Advanced checked them because that's where they are warrantied. Was hoping it would be batteries so I could fix it for free.

I would change batteries before changing starters if Advance checked them.


All your symptoms sound like a shorting or weak battery to me.

 

[Downey]

I completely agree. But idk how to get them warrantied if there thing won't say there bad.

 

[DEEZUZ]

Ac compressor/clutch locking up?

 

[heavydoc]

I have never tried it but I have been told a few drops antifreeze in the battery cells will kill a battery.

 

[Downey]

I have never tried it but I have been told a few drops antifreeze in the battery cells will kill a battery.

This would make sense since my truck puked coolant all over the driver battery pulling camper home for sc.


But up date.
Had them replace the batteries even tho there machine said they were good and no problems. Now but the morning will tell the true story.