The 1975 Mazda 929 is equipped with a 12 volt battery consisting of six cells which capacity is 50 Ampere hours of 20 hours rating. The 1975 Mazda 929 engine electrical system consists of charging system, starting and ignition system. If the electrical system is not charging properly, it is advisable to determine whether the trouble is in the alternator or regulator prior to removing the alternator.
Charging System Checking Procedures:
- Disconnect the wire from "B" terminal of the alternator and connect the ammeter with the negative lead of the ammeter to the wire and the positive lead to the "B" terminal. (see below diagram for detail)
- Disconnect the coupler from the regulator. Connect the disconnected couplers with the suitable wires.
- Start the engine and take reading of the ammeter, holding the engine speed to 2,000 rpm.
- Disconnect the wire from the "F" terminal and short circuit the wire to the "A" terminal for a moment.
- If the meter reading increase remarkably, the trouble is in the regulator and if there is no change in current, it is in the alternator.