can manifest itself in a high electrical resistance at that connection this in turn manifests itself in a relatively high voltage drop across that connection thus to diagnose a high resistance connection voltage regulator 26 performs the routine illustrated in fig3 at step 302 voltage regulator 26 measures the voltage at the positive terminal of battery 19 at step 304 voltage regulator 26 determines whether the charging system is operating u201c within regulation u201d by comparing the voltage at battery 19 to a regulation threshold typically 13 5 volts if the battery voltage is below that threshold it is inferred that the alternator is operating at u201c full field u201d i e darlington transistor 48 is fully u201c on u201d to try to increase the output of the alternator in this case the output current of the alternator is likely to be quite high with a correspondingly high voltage drop across the connection between terminal 21 and conductor 23 in order to prevent false indications of a high resistance fault the fault detection routine of fig3 returns to step 302 under this circumstance if alternatively the answer at step 304 is no the voltage at output 20 of rectifier 143 is measured step 306 at step 308 the two measured voltages are compared if they are greater than a threshold voltage it is determined that a high resistance connection exists between output terminal 21 and conductor 23 this determination can be made because given ohm 39 s law a higher resistance between output terminal 21 and conductor 23 will cause a greater voltage drop across that connection the threshold voltage may be.