[MrMegee]

I bet the radiator mounted fan switch is bad.

How would we check this? Quite new to electrical diagnosis.

This. Or just unplugged even. It’s on the pass side down low, near where the lower rad hose connects to the rad. Start here and work your way back.

Do the fans work when you turn on the AC? They should always come on when the AC runs. That will give you an idea if the fans or their wiring is suspect.

No we put the A/C on full blast, nothing. That switch is plugged in, and its actually a new part.

Check the relays in the small fuse box on the passenger side of the engine compartment

Okay. How do we check that? Just listen?

 

[MrMegee]

What I would do is with the car running. Unplug the coolant fan temp switch on the bottom passenger side of the radiator. Jump the wiring harness pins together with a paper clip or a small length of wire. See if the fans come on. If they do then replace the rad fan temp switch. If they don’t then check the fuse as I showed you above. If that is NOT blown then move to the three relays. They should make audible clicks when you test them. You can test them by pulling them out and apply voltage directly to them to listen for a click.

Okay will try the paper clip thing. The fuses are both good, that was the first thing checked. How would I apply power to the relays directly? And the fans? How would I apply power to those?

If the fans dont come on with the AC then its most likely not going to be the temperature sensor. More likely the relays to power the fans, the wiring to the fans or even the fans themselves.

I think from memory there are 2 fan relays, pretty sure you can swap one of them with the relay next to it (horn?) to test it out.

There are 4 fan relays any idea on which goes to what?

 

[MrMegee]

Yep just look inside the cover. Sorry didn’t think I had to also take a picture of that 😑

Yeah. I did look in the cover, was just wondering which Relay went to each fan... but I guess it doesn't matter. So, from what I understand, the power goes from the Battery > 30A Fuse > Relays > fans. The fan switch at the bottom of the radiator sends power to the relays which tells the fans to kick on. So.... if i disconnect the Switch at the bottom.... would the fans turn on? I figure if it can't read anything from the switch it will just turn the fans on. I could be wrong. Really trying to figure this out.
IF that does work, would the switch / wiring be the problem?
If that doesn't work...would it be the relays?

Sorry the picture is so crappy it wants me to be a vip member to upload full resolution. Also just in case anyone reading this is ever looking for the diodes that are in the diagram. For some stupid reason Toyota decided those diodes should be in the passenger side(RH) kick panel.

Sent from my PH-1 using Tapatalk

Thanks for this. Helps me understand the wiring a bit more. Fairly simple system.