[Loomis]

I have a 2003 350Z with 129,000 miles. Th other day while I was inside a store I left the car running with the a/c on. When I came out the temp gauge was at the top of the first section of the gauge. Not up to the H mark. I drove about 2 miles to get it to cool down. Looked on you tube for info and saw a video that showed crossing the connections in the fan relay behind the battery. It showed connecting the 2 right terminals turning on the right side fan and the two left terminals tuning on the left. side fan. I tried that and the driver side wouldn't work. So I replaced the fan. Still the same. This morning I discovered there are 3 fan relays. The top one works the pass. side and the bottom one works the driver side. Middle one has no effect. When I turn on the a/c the pass side fan comes on. After warming up it continues to run with the a/c off. The drivers side never comes on but it is not overheating again. I was under the impression that one fan was for the a/c and the other was just a cooling fan. What is actually going on?.

 

[dkmura]

I can't tell you how to fix your Z. But the two fans operate under different conditions. One is used for low-speed operating and on particularly hot days, the second kicks in under high-speed conditions to augment the cooling. Both fans are needed under heavy heat conditions and are controlled by the ECM through a relay. I'd suggest you stop playing with the wiring before something else gets screwed up.