1989 Mercury 200hp not charging

Answer 1

 my girlfriens '89 marquis had this same charging problem. although there can be diferent reasons for a not charging scenario,mine went like this. the car would not start sometimes,would have to jump it off. got a new battery,same thing happened. got a new alterantor,same thing happened. ok....FORD brands have fusible links in their system. first i charged the batttery up to a full charge,then went to the alternator,pulled the big connector off. using a multimeter,(or a test light if available),i checked for 12 volts at the BATT terminal on the connector,i had nothing. i next went to the smaller connector on the alternator at the regulator,and checked for 12 volts at A terminal,bam! 12 volts,ok,next i checked for voltage at the I terminal(battery indicator),voltage here also. ok,reconnect the connectors and followed them down towards the drivers side fender. the BATT wire turns into 2 wires(black/red) connected together by a connector,then go into a fusible link. i checked for voltage on the in coming side of the fusible link(side coming from fender going towards alternator),no voltage. i checked the 2 BATT terminals,still none. the A terminal had voltage. ok,the wire harness from the connector goes up to the front of the car thru the headlight area over to the passenger side fender,comes out at the side of the battery,with 2 fusible links,one for the A  wire and one for the BATT wire,connected to the positive(+) side of starter solenoid. ok,i checked for voltage on the positive terminal of solenoid,i had 12 volts,then i moved down to the A and BATT wires,with the poined end of the multimeter test probes(or test light),i checked for voltage before and after the fusible links. they both had voltage before and after the links,so they were good. now,since i had power on the A wire all the way to the alternator and none on the BATT wire at the alternaor,that meant that somewhere after the fusible link up to the other side is a problem. i started looking at the wire harness from the battery side down towards the headlight area and i noticed that the metal where the wire harness traveled had a burnt arc look to it. i disconnected the battery,removed it,and pulled the wire harness up as much as possible and twisted it around to check the wires,and low and behold,there it was,the BATT wire had rubbed against the metal hole and burnt clean in half ! so,i broke out the wire conector kit,connected the wire back together,wrapped it up with electrical tape,reinstalled battery,rechecked for voltage over at the BATT terminal on alternator,12 volts ! hooked up reader and watched as i started car,the voltage output was 14.5 volts. back in action ! now this was my charging situation. like i stated earlier,there are many reasons for a car not to charge,but going thru all the checks are pretty much the same. if all links,battery voltage  and wiring is suspected to be good,have alternator checked at auto parts store for free. so,check for voltage at all the places thats supposed to have voltage,BATT,A and I(when you switch on ignition) terminals,before and after the fusible links,and then its a process of elimination between the battery and alternator.