my nephew brought his 93 f150 with the 4.9 straight 6 over because after replacing the battery, alternator, and starter selinoid relay, it still wont charge the battery. running i get 12.18 volts at the battery and the longer the truck runs the lower it goes. The engine dies if i disconnect the battery. I was wondering if anyone can help me with that. the alternater has been taken back and tested good. i was wondering if anyone has a wiring diagram of the charging circuit too.

 

They should just have a bump button.

 

Alt won't charge unless triggered by bat voltage.

Left a fuse link off at fender mounted starter relay, or have a bad connection in yel-wht feed to alternator.

Test the yel-wht wire at the alt, should read constant bat voltage. If not trace it back find the fault.

Fuse link should be "Dark green J". Fuseable link can corrode where crimped at either end, causing loss of continuity yet appear fine otherwise.

 

Aight. i let it sit a few weeks because Ive been busy but finally, I fingered it out. the alternator has an internal regulator. it needs to turn on to charge the battery. the way it happens is when you turn the key to run, 12 volt power is sent from the ignition switch via the Red with light green stripe wire into the gauge cluster, through the battery gauge, then out of the cluster on the light green with red stripe wire that runs to the alternator. I was not getting 12 volts out of the cluster to activate the regulator, so no charging. being a big piece of junk i just put a jumper wire at the back side of the cluster in the harness plug from the red with light green stripe to the light green with red stripe and viola 14.56 volts charging the battery. I suggested my nephew get a cluster but he probably wont. thought I'd share in case someone searches the forums on the subject.

 

Did he replace the cluster with one with a tachometer in it from a 1994 or 1995 truck? If so that is why it is not charging.
Your path through the cluster is right. The path goes through the charge lamp an the charge resister around the charge bulb.
The diagram below is for a Bronco but the wiring is the same.

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that diagram is identical to the one I asked for in my original post. the same one I had to search high and low for. and no the cluster is original. but the path is open some how within the cluster and i didnt care to troubleshoot it. the 500 ohm resistor checked out ok. thats as far as I went into trouble shooting the cluster. i just bypassed it with a jumper at the plug on the cluster. like I said its a $600 daily beater and not worth replacing the cluster.

 

I recently replaced my old cluster with one that has a tach. I have replaced battery and alternator but the battery won’t stay charged. Can you help me solve this issue?

i don’t know how to make sense of the wiring diagram you posted.

I used a cluster from that year (95) vehicle. Mine is a 96. I followed the previous posts wiring instructions but the truck ran out of juice after a min or so.

 

You should start your own thread. What year truck do you have and what year cluster did you swap in? There are groupings of years that are plug-n-play. If you did not use one of those then some re-wiring is required. Based on your symptoms, no charge, you most likely used a cluster from a non plug-n-play year.

 

I have a 96 f-150. I used a cluster from a 95. I'm not sure how to say what cluster it is.

 

A 1995 into a 1996 would not effect the charging.
They are wired and the pin-outs are the same.

The only problem as I recall is with the ABS with that change.

 

It might have been a 94 but it wasn’t from older than that. Would it be a problem if it was a diesel?

im just trying to think of what could be the problem.

 

No a 94 will still charge OK and the diesel would also.
The only difference would be for the tachometer between the Diesel and the Gas.

 

I would swap the original cluster back. You only changed one thing. Keep it simple. If the problem started after the cluster change, then let's hope it's just that problem.

That will give us a baseline.

Also, did you swap any bulbs out and if so, did you use LED's? Be sure the bulb for the battery light is functioning.

 

I did just that. Original cluster is working fine. Battery is no longer draining. Just wish I didn't buy a new battery and alternator first. I did some more research and apparently a diesel cluster will not work. I think I may have removed it from a diesel truck at the scrap yard. Thanks for the help.

 

Not true.
Both Gas and diesel from 1994-1996 use C250 with pins 1 & 14 for charging.
Sounds like you got a 1992 or 1993 cluster or the cluster has a bad PC, resister and or bulb.



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