92 cooling fan and code 45

Hope someone can help,
I have a 92 with the twin cam 1.9, the cooling fan does not come on when the engine heats up. It will come on with the a/c. Also sets a code 45 and the high idle stays on until well after it is warmed up. Sounds like a bad coolant sensor, right? My question is that if I jumper the two wires for the sensor the fan should come on, but it does not. I jumper the terminals and check for a ground at the relay and no ground. I do not have a schematic but am assuming that the computer provides the ground, any ideas?

Thanks in advance,
KCD

code 45. Oxygen sensor indicates system rich. check/change the O2 sensor, if you still have the orginal ECTS, change it anyway, get the new redesigned all-brass ECTS. the old design cracks pretty easily. i don't have a wiring diagram with me, but i beleave the pcm does provides the ground. there are wires to jump to test the fan, but i don't think the ECTS is one of them. but you say it comes on with the A/C, so we know it works. if new O2 and ECTS sensors don't fix the problem, then clean the fuel injectors. BTW hows your gas mileage?