87 Bronco 2 electrical help needed.

[jose87bronco11]

Yes, should be no lower than 12.8v with key on, if battery was 13v

But alternator is bad in any case, well voltage regulator inside it is, if it outputs more than 15volts running

Thank you now i know what I am dealing with. I learned how to use a voltage meter.
Will replace Alternator and check green wire to Ignition Switch Thanks Again

 

[jose87bronco11]

Yes, should be no lower than 12.8v with key on, if battery was 13v

But alternator is bad in any case, well voltage regulator inside it is, if it outputs more than 15volts running

 

[jose87bronco11]

Yes, should be no lower than 12.8v with key on, if battery was 13v

But alternator is bad in any case, well voltage regulator inside it is, if it outputs more than 15volts running

Update I did have the Alternator tested at Napa and Oreillys 2 weeks ago and tested good at both parts stores. Well machines are not always right Thanks to RonD And Ericbphoto a manual voltage meter test proved it was the Alternator that was bad replaced it problem solved holding a charge

 

[RonD]

Good work

Thanks for the update, it WILL help someone else down the road

 

[4x4prepper]

Unhook the battery, remove the dash panel, and look at the connector for the headlamp switch and look for burnt and melted wires inside the connector.

Then remove the instrument panel and look where the IVR attaches to the printed circuit board with the 9 V battery looking connectors and see if the traces are still there. Then look at the back of the printed circuit where you removed the big square wire connector and see if the traces have been melted off inside the well.

With 18.8V I would suspect the voltage regulator is fried, on my 1985 it is right next to the battery on the radiator support , I think on the 1987 it is on the fender. Check that harness connection for continuity and run a separate ground right from the battery. Sometimes the wires melt right at the connector or just give it up from old age and salt. I use high quality marine terminals on all my vehicles when possible and attach things with ringlet connectors to the 3/8 and 5/16" studs. I have found on the VR that with the wire harness connector being pushed up into the VR, when pushed in they pop out of their place and do not make contact or have a tendency to vibrate loose. I wrap the harness right after the connector with an electrician zip tie (1/4" attachment point), then bolt it somewhere so the connector and wire are constantly pushed into the VR.