91 cherokee hummer

It started with my brake lights . I bypassed the power wire to my break light switch because my brake light switch lost its power source. The next day i drove about a mile and it died it lost spark and fuel we checked all relays and fuses and messed with it for about an hour and it finaly started. Got it back to the shop but it wasnt runnin on all cylinders. so we checked all the plugs and wires and replaced them still no better . So we replaced the cap and rotor and pickup coil . Got it running good again then drove it about a mile and it died again . Since then it blew the dash cluster fuse and died again and hasn't started again . I also replaced the ignition switch and still nothing. It still doesnt start. It seems like the fuel pump works then doesnt then it will get spark then stops getting spark . But now it gets neither and I'm runnin out of hair to pull out so please someone tell me what it is....