Wont Hold A Charge

[jprevat]

I have an 89 B2 4x4 that I put a brand new battery into a couple of months ago. For a while it did great. It cranked every time and had no trouble spinning the starter.

All at once it decided it wont hold a charge. I can put the charger on it all night crank it in the morning just fine but when I come back around lunch I get nothing. The dome lights are even too dim to shine.

I know I have a drain somewhere but I have no idea how to even begin looking for it or what tests to perform.

Any advise would be great.

Thanks in advance guys.

 

[alwaysFlOoReD]

I'm not good at diagnosis of electrical but I'll start off with....
It could be a bad battery. take it to someone that can do a load test on the battery. If it's good then....

Using a volt meter, connect at the battery negative by removing the cable from the battery and connecting [IIRC] the -ve end of the meter to the -ve battery post. Connect the +ve lead of the meter to the loose -ve battery cable. The meter should be reading close to 0 but some [most newer] vehicles will have some reading because of radio clocks and other computer related stuff. I think under a volt is OK but again, I'm not electrically knowledgeable.... So now.... remove the fuses one at a time until you find the circuit that is causing the drain. Now you've reduced the area you have to look. That's about as far as i can take you, hopefully someone else can explain further or correct my mistakes.
Good luck,

Richard

 

[jprevat]

I'm not good at diagnosis of electrical but I'll start off with....
It could be a bad battery. take it to someone that can do a load test on the battery. If it's good then....

Using a volt meter, connect at the battery negative by removing the cable from the battery and connecting [IIRC] the -ve end of the meter to the -ve battery post. Connect the +ve lead of the meter to the loose -ve battery cable. The meter should be reading close to 0 but some [most newer] vehicles will have some reading because of radio clocks and other computer related stuff. I think under a volt is OK but again, I'm not electrically knowledgeable.... So now.... remove the fuses one at a time until you find the circuit that is causing the drain. Now you've reduced the area you have to look. That's about as far as i can take you, hopefully someone else can explain further or correct my mistakes.
Good luck,

Richard

Thank you for the ideas. It will surely get me farther than I am right now.

Is there a place I can find what the fuses under the hood correspond to?

 

[alwaysFlOoReD]

If you have the manual in the glove box. Also I'm sure it would be on site somewhere but I don't know where exactly. Use the google search button at the top right of any page.
ps; make sure the battery is fully charged before load testing.

 

[jprevat]

If you have the manual in the glove box. Also I'm sure it would be on site somewhere but I don't know where exactly. Use the google search button at the top right of any page.
ps; make sure the battery is fully charged before load testing.

I dont believe there was a manual with the truck when I bought it in 2000.
I will look around and hopefully find something to help me out.

If I put it on a 2 amp trickle charge for a couple of days would that do it?

 

[alwaysFlOoReD]

If the battery isn't totally dead then a trickle charger on an isolated battery is better than nothing. I don't know enough to say if it would suffice. But the place you go to should be able to top it off.

sent while sitting on the throne

 

[saskbill]

When the alternator goes bad on these late 80s/early 90s fords, it typically manifests as a short when the motor is shut down - ok when you are driving around in the day, but will drain things flat overnight. If you are trickle charging, def disconnect the battery from the system overnight, and whenever the truck is shut down for very long, 'til you get this diagnosed and repaired.

Between Rangers and mustangs, I've seen this happen so often that when I see this happen, I don't poke around - just disconnect battery when engine shut down and get a 'new' junkyard alternator in as quick as possible - if issue goes away, that's your problem

 

[jprevat]

When the alternator goes bad on these late 80s/early 90s fords, it typically manifests as a short when the motor is shut down - ok when you are driving around in the day, but will drain things flat overnight. If you are trickle charging, def disconnect the battery from the system overnight, and whenever the truck is shut down for very long, 'til you get this diagnosed and repaired.

Between Rangers and mustangs, I've seen this happen so often that when I see this happen, I don't poke around - just disconnect battery when engine shut down and get a 'new' junkyard alternator in as quick as possible - if issue goes away, that's your problem

Thank you very much. I will do this as soon as I get home.

 

[jprevat]

Just an update so everyone else can have the answer too. It was the alternator. I unhooked it from the charging system and trickle charged my battery, once it was fully charged I let it sit overnight (more than enough time to kill the battery before) and it cranked right up this morning.

Thank yall very much.