Servicing the Generator

To test the generator or alternator for output, you must have a new or fully-charged battery. Otherwise,the charging circuit cannot be tested accurately.

Determining type

Determining type "A" or "B" gener-ator circuit. Check the generator belt tension. Now, find out the type of generator you have, "A" or "B." As a rule. type "A" is used by American Motors, General Motors, and Chrysler, and type "B" is used by Ford. Remove the wire attached to the "F" terminal of the generator, and tape the end of the wire to prevent a shod circuit. Connect the voltmeter positive lead to the generator "F" terminal and the negative lead to ground. Start the engine and operate it at a fast idle. If a voltmeter reading is indicated, the generator is an "A" type. If not, it's a "B." Switch off the engine, reconnect the wire to the "F" terminal, and remove the voltmeter.

Testing type "A" generators for output. Locate the voltage regulator, either on the fire wall, the inner fender pan, or the radiator support. Disconnect the wire attached to the "F" terminal of the volt-age regulator, and attach one end of a small jumper wire to the disconnected wire and the other end to the base of the voltage regulator which is grounded. Connect the voltmeter positive lead to the "BAT" terminal of the voltage regu-lator and the negative lead to a good ground. Start the engine and operate it at a fast idle. The voltmeter reading should be at least 15 to 16 volts. If it is not, the generator is defective.

Testing type "B" generators for out-put. Disconnect the "F" and "A" wires at the generator, and tape the wire ends to prevent a short circuit. Connect a small jumper wire between the "F" and "A" terminals of the generator. Connect the positive lead of the voltmeter to the "BAT" terminal of the voltage regulator and the negative lead to ground. Start the engine and operate it at a fast idle. The voltmeter should read 15 to 16 volts. If not, the generator is defective.

Removing and replacing
Removing the generator. Remove the negative battery cable, and with the cor-rect size combination wrench, take off the wires attached to the generator ter-minals. With masking tape, use your own code to mark the wires for correct reinstallation. With a combination wrench, remove the adjusting nut and loosen the mounting nuts or bolts. Push the generator inward, toward the engine, to release the fan belt. Then remove the fan belt from the generator pulley. Remove the mounting bolts or nuts from the generator and remove the generator itself from its mounting.

Replacing the generator. Install the re-placement generator and reconnect all wires to the generator terminals. Con-nect the fan belt and adjust the belt ten-sion. Connect one lead of a jumper wire to the "BAT" terminal of the voltage regulator. Now simply touch the other end of the jumper wire to the "ARM" ter-minal of the voltage regulator. That's all you have to do to polarize any gener-ator. Disconnect the jumper lead. Cau-tion: Type "A" generators are not inter-changeable with type "B." You must replace the