Radiator fans

pontiac
bonneville

#1

1997 bonneville 3.8,fans do not run.changed water pump last year.new failsafe thermosate,fan switch,fan relay switch,flused and filled with dexcool.fans work with direct power from battery.tempeature gage just keeps climing into the red zone.any answers


#2

Do they run when you turn on the A/C?? If so, the thermoswtich that controls them has failed or is not connected. If not, start at the relay and see what is wrong…


#3

Did the fans work after all those switches and relays were replaced at the time of the water pump replacement last year?

If so, one of the components has gone bad since last year. The fans themselves seem to be OK, so it’s something in the circuit. I’d suspect the coolant temp sensor that triggers the fans or the fan relay.


#4

I doubt the fan relays are getting electrical power. Check #6 fuse, and check the power (12 volts) gets from the #6 fuse to the fan relays. The fans’ relays are controlled by a dark green wire, and a dark blue wire, from the engine computer. When the engine gets hot, check for voltage (maybe, 5 volts, maybe 12 volts) at the relay sockets, on those wires from the engine computer.