I had the same problem with my '92 SHO with circuit # 8. It also affected my radio. It was very intermittent and would blow a fuse every few days. I tried to identify where the short was and was unable. I had a really good mechanic work on it for an hour and he was unable to narrow it down, also. I finally went with an automatic resettable fuse and it has been fine for the last few years. I think there must be a slight break in the wire insulation somewhere that momentarily shorts to ground every so often with a bump in the road, etc. It was the only way I was able to take care of it, short of replacing the entire circuit/ wiring harness. Good luck!