KE10 Corolla Charging circuit and external regulator


Toyota Corolla KE10


The alternator light comes on on dash board that warns you that the alternator is not charging, what is faulty, external voltage regulator or the alternator its self.


being a very early model vehicle, with external regulator we had forgotten how these systems worked it was time to get out thinking caps on as it had been a while. The Alternator light was on in the instrument cluster, this sort of vehicle has the alternator which might be referred to in the early days as a generator, none the less we still had to work out if the regulator was at fault or the alternator didn’t produce enough current to turn the charge light out.KE10-corolla-Alternator-NEW-unit

The back of the alternator has three wires and the voltage regulator has 6. depending on exactly which system you have and whether or not the voltage regulator has been exchanged with a later electronic version, testing of the alternator on the vehicle will still be the same.

We pulled apart the voltage regulator and found that the relay was not being pulled in by the alternator, when the relay was clicking manually the alternator would charge, we thought this was strange and they alternator was working a typical voltage regulator fault, going from memory and previous experience, we decided to check a workshop manual and look for  what clicks in the relay sure enough the relay is  6 volt relay and clicked in by the F circuit, when the F circuit does not exist due to the faulty alternator the power circuit will not work as the rela is not clicked in for the output circuit to operate,




Replacement Bosch alternator