So, my son purchased a 1995 Mighty Max that is all beat up. Been working for months to get it running but now I have an issue with the battery charging. I have changed the battery, started, and alternator already and it will crank and run. But using a volt meter I notice it will loose power right away. Any help would be appreciated, things I have confirmed:
- When truck is off testing the batter I get 14-16 volts
- Tested terminal to terminal
- Tested connector to connector
- Tested negative cable to main fuse box (this is there the main fuse and 80AMP charging fuse is located)
- Tested from negative to the junction box by the drive side firewall. When off 2 of the 3 have the same voltage.
- When jumping (truck no running just passing current from another car)
- Tested all the above and getting 19-20 Volts
- When truck is cranked it drops to about 10 volts but once running it goes back to 19-20 volts
- At this point the 3rd jump on junction box (this is the one going to the main fuse under dash) now have the correct voltage.
- Once I remove the jumper cables the batter started loosing voltage until the truck finally dies.
I have traced as many cables as I can and I confirm:
- power from alternator is running to firewall and then over to junction.
- two cables from alternator is going inside cab to a junction under passenger kick plate
- starter is powered directly to postive terminal and than the metal connector to main fuse box which has voltage confirmed.
- checked all the ground cabled and cleaned any rust spots before tightening back down.
Question, based on the wiring diagram looks like there might be another fuse or really coming from alternator for voltage regulation. I noticed on the passenger kickplate there is a gold.brass box just below the junction panel. Is this a relay fo capacitor for the voltage regulation?
Once again thanks in advance for help, trying to make this a father/son project and avoid taking to a shop.
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