Could be an accessory that has been left on unnoticed i.e. glove box light trunk light etc. Could be an excessive parasytic load Could be a bad voltage regulator not opening when vehicle is shut down Could just be that the battery is worn out and cannot hold a charge
Disconnect the 1988 Century battery. Remove the alternator battery. Disconnect the alternator wiring, then unbolt the alternator. Bolt in the new alternator, then reverse the procedure to finish the installation.
If it is running on the battery only then that means the alternator is not charging the battery.
Check the fuses, they could be fried.
I have the exact same pproblem with a 1988 tempo, replaced the alternator and battery, still the alternator only reads 5 volts when running. Can't figure it out, do you know of any websites that would have a diagram of the alternator for a tempo?
bad alternator ? its not charging the battery
?ignition control module/pickup
It could be two things. As you know, the alternator charges the battery so it will not drain. If the alternator is not working properly to charge the battery, the battery will continuously drain. Have the alternator tested at your local Auto Parts store (NAPA or Advance Auto) If it is good, have the battery checked.
It is possibley your alternator or battery
To remove the alternator on 1988 Honda CRX the negative battery must first be disconnected. The belt needs to be loosen and the mounting bolts need to be removed as well. When unmounted the alternator will slide off, and a new unit can be replaced.
On a 1988 Mazda 626, the fuel pump relay is located in the fuel tank. Always disconnect the battery before beginning work on a fuel system.
does your bronco have an external voltage regulator if so i would take it and have it checked
try replacing the alternator