I have a 1994 Blazer 4wd with near 270K miles. The fuel injection wire has had problems for over a year and basically keeps heating, insulation melts, wire breaks. It's been fixed a couple of times by different shops which warn that the fix is not guaranteed or permanent, but each time we've gotten 5-6 thousand miles again before the problem recurs. My son tells me that one root cause is heating from burning oil around engine manifold (?) due to high miles. The shops have bypassed connectors and last time crafted a metal collar around insulation to help protect where they soldered wire. He just drove it 500 miles and barely made it back home, said now the wire is deformed as well. The last time we had trouble before that was under the hood where the break was easy to find and fix--we were 900 miles from home, made it back fine and put a few more thousand miles on before the current problem. He tells me replacing the wiring harness would cost $1000 for harness and labor. I can't afford new vehicles and hate shopping for a used vehicle so happy to keep this going as long as I can. But wondering if the underlying problem would likely broil the new harness anyway. Except for this and a new problem with the blower (switch was replaced and worked for quite awhile, now doesn't blow at all) which also seems to dim the dashboard lights (from reading it looks like that could be ignition wiring) the blazer runs great and gets decent mileage. I mostly drive it in town, and not much, but my son takes it on the road as a subcontractor who does computer network installations (he does some of the car basics but not replacing the wiring harness). Thoughts?