The operation of the voltage regulator is to continuously automatically change the generator excitation current in such a way that the generator voltage is maintained within the specified limits when the generator speed and load current change.
You will need: flat-blade screwdrivers, wrench «for 8», tester.
1. Pull out the rubber boot and connect «positive» voltmeter wire to terminal «plus» battery, and «negative» connect the wire accordingly to the terminal «minus».
2. Start the engine and turn on the car headlights.
3. After 15 minutes of engine operation at medium speed measure the voltage, it should be in the range of 13.8–14.4 V. If undercharging is observed (voltage is out of range)...
4.... check the voltage directly on the power output (hairpin) generator relative to its body («masses»). If the voltage at the alternator pin is correct, check the voltage at the power terminal. If the tester shows different voltage values, then strip the contact of the power terminal and securely tighten the nut, then repeat the measurement. After preventive actions, the voltage difference between the stud and the terminal should decrease to zero. If the tester readings are the same, i.e. is normal, then in the same way as described above, check the voltage at the fuses F4 and F6, their terminal blocks and at the place where the harness is attached «plus» battery to total «positive» main fuse box bus. If voltage at alternator pin is not correct, check alternator drive belt tension and adjust if necessary (see «Checking the alternator drive belt tension»). If the voltage is not correct again, replace the voltage regulator.
5. Disconnect the wire from the terminal «minus» battery.
6. Disconnect the block with the wire from the output «D+» generator.
7. Remove the rubber boot, unscrew the nut...
8.... and disconnect the wires from the terminal stud.
Note. The work of replacing the voltage regulator is performed on the generator installed on the car. For clarity, the generator is removed from the car.
9. Turn away a nut of fastening of the plug of a chain of excitation of the generator...
10.... and remove the terminal.
11. Turn away three nuts of fastening of a plastic casing of the generator...
12.... and remove the casing.
13. Turn off two nuts of fastening of the case of a voltage regulator...
14.... screw for fastening the terminal of the regulator to the bus «D+» rectifier block...
15.... and remove the voltage regulator from the generator.
Note. This is how the voltage regulator assembly with brush holder removed from the car looks like.
16. Check the ease of movement of the brushes in the brush holder and their protrusion. If the brushes protrude from the brush holder by less than 5 mm, replace the voltage regulator with the brush holder.
17. Install the voltage regulator in the reverse order of removal.