my 96 gp 3100 has fans that are not working. if im when the temp sending unit reaches the right temp it sends a signal to the fan control relay. or does it send a signal to the ecm which then sends a signal to fan control relay. and does if l remember right it sends the relay a ground signal. because there is always a hot to it. what all could be the problem. l have constant power. my fans work when they are hot wired. and l dont wanna set up a toggle swich. wiring is my hardest subject but is the best task to overcome. what could be the problem
the temp sensor has 3 wires coming out of it.it runs then rises. not too quickly but about as fast as one should runnign with no fan. but not hot at all when it reads 225 and up. hasnt even warmed up enough for the thermostat to release. so im thinkin its the new sensor l just got. so im gonna get another one tomorrow and well see from there

relay is good? may go through the ecm, could send the signal from the temp switch, to the relay, relay coil, or contacts bad?

ECM first, but what about AFTER a coolant temp sensor? Then to relay, ground signal sounds reasonable and correct, with hot present. Replace temp sending unit!

If ur system has single Temp switch

Reading temp is picked up by sensor/switch
runs back to Gauge
gauge runs to & though Ignition switch
to ECM to Fan Relay
to FAN

Relay has power supply from Fusible link & ECM

l still have not found a wiring diagram for ur model.

If gives off 225 temp reading when cool & has a New sensor has a short somewhere. or bad part or connection.

If running & just rises quickly & motor gets hot just as quick u might have 2 problems.

Also if yours system has 2 temp sensors completely differ

Parts list
Temp sensor
fan relay
relay Fuseable link
Gauge
printed circuit
ignition switch
ECM
shorts off ECM
(( low Coolant module runs wire back to ecm ))
Service engine soon through printed circut