To begin with I have had my fans wired to both come on at high speed either when 1) AC is turned on. 2) Low temp sensor is triggered. Just yesterday I noticed that the fans are only coming on in low speed. I double checked my "hotwire" and continuity is good. I have switched the relay from my fogs to the high speed fan relay "in the fuse box on passenger side of engine compartment" with no change. Both fans do turn on with the AC, and both fans do turn on when the low temp sensor is triggered. My main question is would the High temp sensor being out cause the system not to trigger high speed fan operation? This is on a 1993 btw.