its a 3 wire sensor, he is full of ****. When mine went out, the scan gauge read -38 degrees on the coolant temp, dash cluster coolant temp was reading fine, and fans came on with a/c, just not when it would heat up. It was the coolant temp sensor bad. It has one signal that goes to the dash and one signal that goes to the computer. If it goes bad on one end, it will read fine on the dash but will never signal computer to kick on the fans. However, in your case, idk. Maybe another relay that just the computer uses?

Logan