See Figures 1, 2, 3, 4 and 5
The alternator converts the mechanical energy supplied by the drive belt into electrical energy by a process of electromagnetic induction. When the ignition switch is turned ON, current flows from the battery through the charging system light (or ammeter) to the voltage regulator, and finally to the alternator. When the engine is started, the drive belt turns the rotating field (rotor) in the stationary windings (stator), inducing alternating current. This alternating current is converted into usable direct current by the diode rectifier. Most of this current is used to charge the battery and to supply power for the vehicle's electrical accessories. A small part of this current is returned to the field windings of the alternator enabling it to increase its power output. When the current in the field windings reaches a predetermined level, the voltage regulator grounds the circuit preventing any further increase. The cycle is continued so that the voltage supply remains constant.
All models use a 12 volt alternator. Amperage ratings vary according to the year and model. 1970-77 models utilize a separate, adjustable regulator, while 1978-88 models have a transistorized, nonadjustable regulator, integral with the alternator.
To prevent damage to the alternator and regulator, the following precautionary measures must be taken when working with the electrical system.
REMOVAL & INSTALLATION
See Figures 6 and 7
On some models, the alternator is mounted very low on the engine. On these models, it may be necessary to remove the gravel shield and work from beneath the truck in order to gain access to the alternator.
- Disconnect the negative battery cable.
- Remove the alternator pivot bolt. Push the alternator in and remove the drive belt.
- Pull back the rubber boots and disconnect the wiring from the back of the alternator.
- Remove the alternator mounting bolt and then withdraw the alternator from its bracket.
- Position the alternator in its mounting bracket and lightly tighten the mounting and adjusting bolts.
- Connect the electrical leads at the rear of the alternator.
- Adjust the belt tension as detailed in General Information & Maintenance .