As the alternator is "easy" to access for the Zetec, I would suggest checking the regulator at the alternator (regulator costs about $40). It could be the wiring too.

Edit. Regulator removal.
http://www.contour.org/ubbthreads/showflat.php?Cat=&Board=trouble&Number=979000&page=&view=&sb=5&o=&fpart=&vc=1

Location.
http://www.autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/1b/c2/fd/0900823d801bc2fd.jsp

Last edited by Tony2005; 02/27/06 01:09 AM.
"Always do the cheap and easy ones first." 1996 V6 ATX 96K miles