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Honda

1988-1991 Civic/Accord Timers - Charging Problems

When diagnosing charging problems, or checking out the electrical system of a 1988 to 1991 Honda Civic, Civic CRX, CRX Si, or Accord which has just had an alternator installed (p/n AL256X, AL387X, and AL1260X), technicians should be aware of the peculiar characteristics of these alternators.  There is  a special circuit in the voltage regulator of these units which is controlled by the vehicle ECM that can lower the alternator output to less than 10 amps while keeping a 12.6 volt charge on the battery.  

Honda installed a timer to reduce extra mechanical load on the engine immediately after starting.  This timer will wait exactly 60 seconds for everything to stabilize before it signals the alternator to charge.  This timer is set up in such a way that during this 60 second initial start up period no warning lights will come on to indicate any abnormal conditions to the driver.  But, technicians who have just installed an alternator and are checking out the system with a DVOM will see this initial low output and are liable to think that they have a malfunctioning unit.  So...technicians should be alerted to either conduct their initial tests for more than 60 seconds and be aware that this timer delay is built in, or they can override this delay by turning on the headlights or blower motor which will make the alternator charge immediately.

An easy method of identifying these units is by the markings on the alternator regulator plug configuration.  These alternators, which may have either a 3 or 4 prong plug, will have the letter "C" marked in the configuration. 

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