Truck will not start new battery and alternator?

2006 FORD F-150

146,000 MILES • 4.6L • V8 • 2WD • AUTOMATIC

SANTACRUZLOCAL

MEMBER
2 POSTS

While driving all windows up air conditioning on 4 I noticed the output was weak, then all power shut off inside, instrument panel, radio, windows, everything. I parked turned the engine off. Got a jump but couldn’t get it out of park. Installed a new battery drove it home. Even with new battery, battery light kept coming on only while in idle mode, stop lights or in park ect. A couple of days went by and my son replaced the alternator because of the battery light being on. Now the brand-new battery is showing it’s dead, jumping it didn’t work so we are charging it overnight to see if it will start in the morning. A couple hours into charging battery it seems to be taking a charge but I’m still going to wait till morning to see if it’s going to start. I’ve never had electrical issues before and I keep up on all maintenance. Wondering if it could be as simple as a relay?

Sep 22, 2023 at 3:11 PM

JACOBANDNICKOLAS

✓Experienced Mechanic
110,240 POSTS

Hi,

It sounds like even the new alternator isn't charging. We may not be getting power to it.

I attached the wiring schematic for the charging system below so that you would have a reference. Here is what I need you to do.

At the alternator, there will be a black wire with an orange tracer. Also, there will be an orange wire with a light blue tracer. Check both of them for power. They should have battery voltage.

Let me know what you find.

Take care,

Joe

See pics below.

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Professional Diagram for 2CarPros Members
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Sep 22, 2023 at 4:21 PM

SANTACRUZLOCAL

MEMBER
2 POSTS

So, the alternator was fine, a friend looked at it and the connectors to the battery were not tightened enough. It started right up once he did that. He also checked the amps and voltage on both battery and alternator and he said they seem to be right where they should be so thank you, I’m just happy my truck is back on the road.

Sep 24, 2023 at 5:09 AM

JACOBANDNICKOLAS

✓Experienced Mechanic
110,240 POSTS

Hi,

That is a simple fix. LOL Thanks for the update. I'm glad to know you got it going again.

Take care and feel free to come back anytime in the future.

Joe

Sep 24, 2023 at 6:35 AM

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