NO ENGINE TOLD ! 2.0 OR 2.5LITER?????????TH 8TH DIGIT OF YOUR VIN TELLS YOU WHICH ENGINE IS THERE, PLEASE TELL THAT FIRST.The alternator is overcharging. what makes you think so? a meter test.? scan tool shows DTC that said that>? OK JUST FLICKER, lights flicker, what light, heads, or charge lamp error or what? (i guess all) putting in 3 wrong alternators is painful , there are 2 used, here. on 2 enginesone is pcm controls, other is not. The 2 engines and matching ALTs: DURATEC -VE 2.5LITER ONLY ZETEC-VCT 2.0L ONLY THEY ARE NOT THE SAME. ALT ! NOR ENGINES DURA HAS 3 FUSES TO BLOW. BOTH ALTS USE THESE FUSES F30-CJB. 7.5a, CENTERAL JUNCTION BOX. and F2 =BJB, 15AMP BATTERY JUNC. BOX BJB AND FB 175 AMP THE REG IS INSIDE THE ALT HERE, NOT PCM DID YOU REPLACE THE ALT WITH THE NEG LUG ATTACHED, IF YES, THE 175AMP FUSE IS BLOWN BOOM ZETEC USES PCM REGULATION AND SAME 3 FUSES TO FAIL, 1,2,3.. THE 175 FUSE MUST BE GOOD. TOO. THE CORRECT GENERATOR FOR YOU ENGINE MUST BE USED THE DURA and zetec alternator gens can NOT be mixed up here ever! best way to buy any alt is by VIN # code or fail 1/2 the time or even 3times in row. or 175amp is blownif buying over the counter (a new alt) tell them there 2 kinds used in 2000, tell them the vin 8th code.