         
Honda has several variations on there charging systems. ·3 Terminals with D Terminal: Some Civics have only IG and L terminals. The third is a D (dummy) terminal and is not connected to anything. Use the Quick Test Procedure to test only the IG & L. ·3 Terminals with C Terminal: Some Civics (1984-87 HF Models) have a regulator where the S terminal has been replaced by a C terminal. This C terminal is used to vary alternator ouput. The C terminal is controlled by a second computer mounted under the dash, near the fuse panel. To increase fuel economy, the computer will lower the charging voltage to as low as 12.5 volts. If you get one of these Civic HF models in your shop, have an assistant step on the brake pedal while you test the charging system. The computer will sense the draw from the brake lights and turn the voltage setting back to 14.5 volts. The charging system will now test like any other. Read C terminal tips at the end of this section. Use the Quick Test Procedure to test only the IG and L. ·4 Terminal with S or C or D Terminal: Some Hondas have 4 terminals on the alternator. These terminals are: FR - no testing is required L - test with Quick Test Procedures IG - test with Quick Test Procedures The fourth terminal can be S, C or D S - test with Quick Test Procedures D - this is a dummy terminal. No testing of D is required. C - see the section on C terminal tips Quick Test Procedure 1.If carbureted, unplug the electric choke. 2.Remove the plug from the alternator. 3.Turn the ignition key to "run" position. (engine off) 4.Use a test-light to test all three terminals in the car's harness plug. (Not the terminals on the alternator!) 5.Use chart figure 3 to troubleshoot. C Terminal Tips The car's computer uses the C terminal to control the charging voltage. When the computer wants to reduce the load of the alternator on the engine, it grounds the C terminal. This drops the voltage setting to about 12.5 volts. When the computer senses the need for more charging, it removes the C terminal from ground, and the voltage regulator goes back to 14.5 volts. The main point to remember when checking for a charging problem is: If the wire between the C terminal and the computer is grounded anywhere, the alternator will always test "bad". Look for wiring harness rub-through or pinched wires. 
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