Article 2067 - Alternator and Regulator Servicing Tips

TSB #131 - January 16, 1970
(All Vehicles Equipped with Alternator)

Integral Alternator Regulator Assembly - Part No. C8SZ-10316-A



Voltage limiter calibration tests must be made with the regulator operating with battery and ignition loads only.

For accurate voltage limiter testing, the battery specific gravity must be at least 1.230. If the battery is low in charge, either charge it to 1.230 specific gravity or substitute a fully charged battery, before making the voltage limiter test.

To test the regulator on the vehicle, make the test connections to the battery and tester knob adjustments as shown in Figure 13, Voltage Limiter Test.

    1. Place the transmission in neutral or park and apply the parking brake.
    2. Close the battery adapter switch and start the engine. Make sure that all lights and electrical accessories are off. Open the battery adapter switch.
    3. Operate the engine at approximately 2000 rpm for 5 minutes (use a tachometer).
    4. Read the voltmeter on the tester. If the voltage is between 13.3 and 15.3 volts, the voltage regulator is functioning normally.
    5. If the voltage does not rise above the battery voltage, perform a Regulator Supply Voltage Test to make certain that battery voltage is being supplied to the regulator. if there is regulator supply voltage, either the regulator or the alternator is malfunctioning. Perform an alternator output test to determine which is at fault.
Use care when connecting the test equipment to the alternator as the alternator output terminal is connected to the battery at all times. Under no circumstances should the regulator battery terminal be connected to the regulator field terminal. To do so will permanently damage the regulator.
    1. Check the alternator drive belt tension. Place the transmission in neutral or park and apply the parking brake. Make the tester connections as shown in Figure 14, Alternator Output Test. Connect the jumper wire as shown. Be sure that it is securely clipped to the regulator field terminal.
    2. Close the battery adapter switch. Start the engine, then open the battery adapter switch.
    3. Increase the engine speed to approximately 2000 rpm. Turn off all lights and electrical accessories.
    4. Turn the master control clockwise until the voltmeter on the tester indicates 15 volts. Observe the ammeter on the tester. The reading should be between 50 and 57 amperes. If the alternator performance is O.K., the trouble is in the regulator.
    5. Return the engine speed to idle before releasing the master control knob.
If the alternator output is not O.K. with the regulator bypassed, the problem is in the alternator. It will be necessary to remove the alternator from the vehicle and perform the necessary bench tests to locate the defect.

An output of 2 to 8 amperes below minimum specifications usually indicates an open diode rectifier. An output of approximately 10 to 15 amperes below minimum specification usually indicates a shorted diode rectifier. An alternator with a shorted diode will usually whine, which will be most noticeable at idle speeds.
    6. If the regulator has been found malfunctioning and the replacement regulator also malfunctions after a short period of operation, check the ignition switch and terminal connections for intermittent operation. An intermittent ignition switch contact or wiring open or short circuits can cause integral regulator malfunctions.
For 1970, the integral regulator system was installed on Thunderbird, Lincoln and Mark III units. However, as of October 1, 1969, the integral regulator system in being installed only on the Mark III units. All other units use the mechanical regulator. Therefore, large inventories of integral regulators in stock will not be required.

    1. If it is necessary to replace an alternator diode assembly, always remove stator wires by unsoldering rather than clipping. Stator wires are manufactured to a critical length to prevent shorting to the alternator housing or prevent excessive pulling on the diode assembly.

    All diode and rotor assemblies are date stamped. Therefore, all parts recalled by the Warranty Parts Return Center are checked against the vehicle data for part date validity. To expedite prompt claim repayment, insure that the right part accompanies the right claim. Printed diode circuit boards with exposed copper strips were last used in production 11/14/67.

    2. All 1970 units have alternators with coarse threads on all terminal connecting studs with the exception of early built light trucks from the Michigan Truck Plant.

    3. All returned alternators to the Warranty Parts Return Center must be completely assembled and contain all parts properly installed including rotor brushes and springs.