tcrisp

dual fan do not work unplug relay and stuck a paper clips in the connector and fan came on . bought new relay put in still do not come on info would be great to get this problem fix

Injuneer

Year of vehicle, and engine type needed.

Do you mean neither of the dual fans work, or only the "AUX" fan does not work?

I've got the Chilton's 3rd Gen wiring, but each year/engine variant can be a bit different. On the dual fans, it appears one is controlled by the ECM based on a coolant temp sensor input, and the other by a separate cooling fan temp switch. The signal side of the two fan relays receives 12V from the same 20 amp "C/H-FAN" fuse.

tcrisp

1989 camaro iroc 350 tpi and have both the fan temp switch and the coolant temp sensor got this car and the engine was a long block still in the car and nothing was tag to tell me where it go i was wonder if i needed both sensor

Injuneer

If you want both fans to run, you need both the sensor and the switch.

Coolant temp sensor, feeds the ECM, 1 yellow wire, 1 black wire to the connector, is on the front of the intake manifold, under the throttle body, near the water outlet. Sort of hard to see.

Aux fan coolant switch is a single black wire (or possibly gray), located on the passenger side head, between the 2 rear spark plugs.

There s a third sensor on the driver side head, but that's for the gauge in the dash, does not control fans.

tcrisp

i check to see if i have voltage going to the ecm and i had the correct volt i guess i will check the fan switch next and see if it is bad . than i will see what is next

smokin25th

Checked both fans. One is for the motor and the other is when the A/C is used it seems.