Bad Alternator?

[WHRoeSr]

68 Bronco. Just got it out of the body/paint shop after 1.5 years. Bugs are popping up now.

Appeared to have a bad battery (had to charge up a couple times) when leaving the paint shop so replaced it with new. This was 4 days ago. Was starting and running fine until last night. Cold starts not a problem - fired right up every time with the new battery. Last night while driving, my aftermarket radio was powering on and off. And the newer H4 LED headlights seemed to be on low light output but it had been quite a while since I had driven at night so I wasn't sure about that.

This morning on a cold start, it reluctantly fired up on first crank. Didn't think much of it. I drove it 2 miles down the road to a gas station to fill up. After it was gassed up, tried to start, and nothing. Would not turn over. A good samaritan stopped and jumped me. Took several minutes to charge up the battery enough to start it. Drove it 2 miles back to my garage. Shut off the engine and immediately tried to start it again. It started, barely. Shut it off and tried once more. And nothing...wouldn't even turn over.

Alternator is junk?

Thought maybe something was left on and was draining battery juice overnight, but now thinking that the radio powering in and out while driving last night is saying otherwise.

I'm a far cry from being a mechanic. Have not tested anything yet. Thought you all in here could give me some quick pointers!

Thanks in advance!

-Hank

 

[Beau Nugget]

With the key off, you could take one of the battery cables off. When you touch that battery cable back to the battery post, you just removed it from, look to see if there’s any minor sparking, that would indicates that there’s a draw of electricity on the battery even when the truck is off. I’m not talking about a large arc of electricity. Just Very small subtle sparks If there is no draw of electricity from the battery, there will be no response when touching the battery cable back to the battery post— which is what you want.

Otherwise, a bad alternator sounds like a likely reason for your problems

 

[904Bronco]

Fully charge the Batt
Alt belt tight? Terminals on Batt clean and tight?
Turn the key to run, does the field wire (Green/red stripe) have Battery voltage.
Is there batt voltage at the Batt terminal on the Alt?
Does the voltage at the Batt rise once you start the rig up?
Amp gauge show charge, assuming you still have that...

 

[m_m70]

I would start with getting the battery fully charged. A two mile drive is nowhere near enough to charge your battery. But that doesn't explain why it's dead in the first place.

How old and clean are your cables??

get yourself a voltmeter or better yet a multimeter and start checking for voltage. With your volt meter, you should be able to see if your alt is charging and I would start there.

Lots of stuff can cause what your experiencing. Usually, pretty easy to fix.

 

[gnpenning]

As mentioned you are going to need a multi meter to isolate the problem.

You just got it from the paint shop, was it painted under the hood?? Check.ground connections.

You can check your parts store and see if they have a alternator tester and battery tester. Be aware that the battery has to been charged or attempted to first.

Do not start throwing parts at it until tested and proven bad.

 

[m_m70]

Do not start throwing parts at it until tested and proven bad.

THIS^^^^

You just got it from the paint shop, was it painted under the hood?? Check.
ground connections.

Soooo important. May explain your stereo issues, dim lights, no charge etc............

 

[DirtDonk]

Did the paint job include a rewire, or just a paint leaving everything together?
If it’s original, you should be watching your ammeter. Hopefully it’s still working after 50 years, but when they worked, they worked very well.
If it’s been replaced the voltmeter you should be watching that as well.
What do the gauges read? Both engine on, and engine off?

Keep a voltmeter handy. Both for those tests described above, and for any checks you may need until you get this resolved.
A voltmeter is any Bronco owners friend.

 

[WHRoeSr]

I would start with getting the battery fully charged. A two mile drive is nowhere near enough to charge your battery. But that doesn't explain why it's dead in the first place.

How old and clean are your cables??

get yourself a voltmeter or better yet a multimeter and start checking for voltage. With your volt meter, you should be able to see if your alt is charging and I would start there.

Lots of stuff can cause what your experiencing. Usually, pretty easy to fix.

Battery was brand new & fully charged a few days ago. Will clean all cables and check voltages!

 

[WHRoeSr]

Did the paint job include a rewire, or just a paint leaving everything together?
If it’s original, you should be watching your ammeter. Hopefully it’s still working after 50 years, but when they worked, they worked very well.
If it’s been replaced the voltmeter you should be watching that as well.
What do the gauges read? Both engine on, and engine off?

Keep a voltmeter handy. Both for those tests described above, and for any checks you may need until you get this resolved.
A voltmeter is any Bronco owners friend.

No rewire, just a paint job and lots of body work including new some new quarters & fenders (from WH ) and a new hood! Ammeter not functioning. Will put a voltmeter on it!!

 

[WHRoeSr]

THIS^^^^



Soooo important. May explain your stereo issues, dim lights, no charge etc............

Yes painted under the hood in fact a new hood was installed. Will check the grounds.

 

[NGABronco]

Does your rig have a voltage regulator???

 

[WHRoeSr]

Does your rig have a voltage regulator???

Yes but it does not function. On my list!

Will be testing with a voltmeter thanks to the helpful feedback from these replies.

R

 

[Oldtimer]

Once voltage regulator is working, charging current has a long path from alternator to battery.
All the connectors need to be clean and tight.
If ammeter is not working, the Black/Yellow stripe wire may not be going thru loop on back of ammeter.



The two bulkhead connectors are in firewall, near driver side valve cover.



The bullet connector is behind speedometer, near ammeter.