Mazda Trucks 1972-1986 Repair Guide

Regulator

Print

1982 and later trucks use an integral regulator, built into the alternator. No adjustments are possible.

REMOVAL & INSTALLATION



Piston Engine
  1. Raise the hood and disconnect the negative battery cable.
  2.  
  3. Disconnect the regulator wires at the multiple connector.
  4.  
  5. Remove the two regulator attaching screws and remove the regulator from the splash shield.
  6.  
  7. Position the regulator on the fender splash shield and install the two attaching screws.
  8.  
  9. Connect the regulator wires at the multiple connector.
  10.  
  11. Connect the negative battery cable.
  12.  
  13. Start the engine and be sure that the charging system indicator light goes out.
  14.  

Rotary Engine
  1. Disconnect the battery ground cable at the negative (-) battery terminal.
  2.  
  3. Disconnect the wiring from the regulator.
  4.  
  5. Remove the regulator mounting screws.
  6.  
  7. Remove the regulator.
  8.  
  9. Installation is performed in the reverse order of removal.
  10.  

TESTING



See Figures 1 and 2

Click image to see an enlarged view

Fig. Fig. 1: Checking the pilot lamp relay



Click image to see an enlarged view

Fig. Fig. 2: Checking the constant voltage relay

The alternator regulator is composed of two control units: a constant voltage relay and a pilot lamp relay.

Checking The Constant Voltage Relay

  1. Use an almost fully charged battery and connect a voltmeter between the A and E terminals of the regulator.
  2.  
  3. Run the engine at 2,000 rpm and read the voltmeter. It should read from 14-15v.
  4.  
  5. If not, adjust the voltage relay.
  6.  

Checking The Pilot Lamp Relay

  1. Using a voltmeter and variable resistor, construct a circuit as shown.
  2.  
  3. Light the pilot lamp.
  4.  
  5. Slide the knob of the variable resistor so that the voltage gradually increases.
  6.  
  7. Read the voltage between the N and E terminals of the regulator. If the voltage is 3.7-5.7v, it is operating properly.
  8.  
  9. Slide the knob of the variable resistor to decrease the voltage. Note the point on the voltmeter where the light will light again. If the reading is less than 3.5v, the unit is working properly.
  10.  
  11. Disconnect the test instruments.
  12.  

ADJUSTING Piston Engine



See Figure 3

Click image to see an enlarged view

Fig. Fig. 3: Measurement and adjustment points for the voltage regulator

  1. Check the air gap, back gap and point gap with a wire gauge. If they are not within specifications, adjust the gap by bending the stationary bracket.
  2.  
  3. After the gaps are correctly set, adjust the voltage setting. Bend the upper plate down to increase the voltage setting, or bend it up to increase the voltage setting.
  4.  

Rotary Engine

  1. Remove the cover from the regulator.
  2.  
  3. Check the air gap, the point gap, and the back gap with a feeler gauge (see illustration).
  4.  
  5. If they do not fall within the specifications given in the Alternator and Regulator chart above, adjust the gaps by bending the stationary contact bracket.
  6.  
  7. Connect a voltmeter between the A and E terminals of the regulator.
  8.  

Be sure that the car's battery is fully charged before proceeding with this test.

  1. Start the engine and run it at 2,000 rpm (4,000 alternator rpm). The voltmeter reading should be 13.5-14.5v.
  2.  
  3. Stop the engine.
  4.  
  5. Bend the upper plate down to decrease the voltage setting, or up to increase the setting as required.
  6.  
  7. If the regulator cannot be brought within specifications, replace it.
  8.  
  9. When the test is completed, disconnect the voltmeter and replace the regulator cover.
  10.  

 
label.common.footer.alt.autozoneLogo