HAD A SIMILAR PROBLEM WITH MINE .
TRY CLEANING THE BATTERY TERMINALS AND CLAMPS.
ALTHOUGH THERE MAY NOT BE ANY OUTWARD EVIDENCE OF CORROSION. DUE TO THE MINIMAL CONTACT ON THE POSITIVE CLAMP IT ONLY NEEDS SLIGHT PITTING TO CAUSE PROBLEMS.
IT WORKED ON MINE I CAN'T GUARANTEE IT WILL WORK ON YOURS BUT IT'S WORTH A TRY AND IT'S FREE
DFM
August 2007