1991 Jeep Cherokee

Electrical problem
1991 Jeep Cherokee 6 cyl Four Wheel Drive Automatic 233, 00 miles

1991 cherokee. Alternator & battery both tested OK.
Gauge reads in red zone. For a week it would read in the red zone at first then while driving the gauge would go to 14. Then repeat every time it was started. When it wouldn't start one day I jumped it & let it run. Gauge never left red zone. I went to drive it to test everything. When I went to pull out all my lights/clock/radio kept flashing on & off and the rpm gauge started dropping to zero and I could tell the engine was cutting out. Any ideas would be appreciated. Its old and beat but I love my jeep. Would hate to see her go!
June 10, 2010.

Check and test fuse no.8 & 16 in the PDC if okay test the ASD relay in the PDC and the SBEC engine control unit left front corner of engine compartment

Jun 10, 2010.