Radiator fan has stopped.

[CostaRicaTalon]

Hey all, noticed my temp light come on today and sure enough; my fan wasn’t blowing.

I crawled back home in low rpm’s to find out I have no 12v at the fan…

From what I’ve seen, the fan controller and everything runs the fan by regulating the ground current. so with no 12v at the fan, it’s safe to assume I probably have a popped fuse or bad relay right?

I’m going to dive in to it tomorrow and see if I have power at the relay, but figured I’d get some forum opinions first.

TIA!!

 

[Hondasxs]

Hi.

The actual fan motor does operate off positive trigger. So it should not have power if the controller is not calling for fan.

The controller box is under the ECU. Under the seat. It's a black box maybe 2x3 inches in size.
However.....
The controller box IS controlled by a ground trigger. Converting it to a positive trigger. The 2 wire connector is the fan.

Sent from my SM-G996U using Tapatalk

 

[CostaRicaTalon]

Dope! Thank you for the info.
Hopefully it’s a fuse or something.

Otherwise, she going to be running on key power

 

[CostaRicaTalon]

So. With her up at temp (2 bars on the dash)
At the relay, I have no power on the black/pink wire coming from the PCM. Does that mean my PCM or fan controller s*** the bed?? (Or obviously a broken wire between the 2)

 

[NTCPrezJB]

Dope! Thank you for the info.
Hopefully it’s a fuse or something.

Otherwise, she going to be running on key power

Site store sells an override switch for the fan. Gives you the ability to turn it on anytime you like.

 

[CostaRicaTalon]

Site store sells an override switch for the fan. Gives you the ability to turn it on anytime you like.

Yesss I see that thank you. Unfortunately being here in the Costa Rican jungle, that $100 part will cost me $150 in shipping and taxes 🥲

Homemade switch coming right up

 

[CostaRicaTalon]

So. With her up at temp (2 bars on the dash)
At the relay, I have no power on the black/pink wire coming from the PCM. Does that mean my PCM or fan controller s*** the bed?? (Or obviously a broken wire between the 2)

And At the fan controller, I have full 14v on the key power pin and 4v on the black orange wire.

 

[CostaRicaTalon]

And At the fan controller, I have full 14v on the key power pin and 4v on the black orange wire.

So it appears my PCM isn’t sending signal to the relay to fire up the fan.

Would that be a correct diagnosis??

 

[Remington]

So it appears my PCM isn’t sending signal to the relay to fire up the fan.

Would that be a correct diagnosis??

New PCM?

 

[Remington]

Yesss I see that thank you. Unfortunately being here in the Costa Rican jungle, that $100 part will cost me $150 in shipping and taxes 🥲

Homemade switch coming right up

Would be cheaper than a new PCM🤷‍♂️
But if the PCM is fubar then that switch aint gonna do diddly

 

[NTCPrezJB]

Yesss I see that thank you. Unfortunately being here in the Costa Rican jungle, that $100 part will cost me $150 in shipping and taxes 🥲

Homemade switch coming right up

Yikes! I’m sure if you PM @Hondasxs he will tell you exactly how to wire up your own switch then.

 

[CostaRicaTalon]

New PCM?

Are you asking if it’s new or suggesting a new one?

 

[CostaRicaTalon]

Would be cheaper than a new PCM🤷‍♂️
But if the PCM is fubar then that switch aint gonna do diddly

Does that switch not just bypass everything and run the fans straight from battery?

From what it seems, it looks like the bypass switches just inject battery power directly to the fan. And with the switch off, it would be the normal stock fan setup. But I could be wrong

 

[CostaRicaTalon]

Now. Let me ask…
That PCM feed to the relay, is it power? Or a ground?
Does anyone know? And if power.. 12v?

Could I simply cut that wire at the relay and just feed it with key-on power? And my fan speed controller would still work as normal to run everything? Or is the fan controller what sends that signal to the PCM to kick on the relay?

It seems that the PCM to RELAY wire is just simply key-on power, but fed from the PCM?

Any input? Thanks

 

[Remington]

Are you asking if it’s new or suggesting a new one?

Does that switch not just bypass everything and run the fans straight from battery?

Not 100% sure on that?
But if it does its prob thermal switched through the pcm to make the fan come on for auto and most likely other things are controlled that way through there. Only saying this from how the PCM’s on the gens i service work. Is the fan mod a good idea? Yes, i have one on my P1, but its still controlled through the PCM, u just have a switch to override if u want to turn it off or on 24/7. Im just a Gen tech so who am I to know🤷‍♂️

 

[CostaRicaTalon]

Not 100% sure on that?
But if it does its prob thermal switched through the pcm to make the fan come on for auto and most likely other things are controlled that way through there. Only saying this from how the PCM’s on the gens i service work. Is the fan mod a good idea? Yes, i have one on my P1, but its still controlled through the PCM, u just have a switch to override if u want to turn it off or on 24/7. Im just a Gen tech so who am I to know🤷‍♂️

Yes there is 2 feeds that come from the PCM. One to the fan Relay and one to the fan controller. I believe the one to the relay is just an on/off where the other controls speed.

I am going to try grounding the dead wire at the relay today (pink/black wire for me) and see if the fan kicks on.

Stay tuned.

 

[CostaRicaTalon]

So. Wire from PCM to FAN RELAY is a ground. (Mine is pink/black)
So I cut it and ran that relay pin direct to a ground and the fan lit right up!!

So I just grounded it to the frame bolt right above the relays and fuses and all is working normally as should…

…For now!

(First pic was while I was testing. It’s all buttoned up nicely now. Just wanted y’all to see colors and where I cut it)

 

[CostaRicaTalon]

Okay. So final verdict!!!!
Everything works great & I may have just found something cool!!

Now when I shut off the engine, the fan stays running for 2 minutes before shutting down! 🤩

Usually it shuts down with key-off but now it stays running like many have wished for, or installed switches to do..

If I want to shut the fan off instantly; after shutdown, I can switch the key back to the “ON” position and then back to off and it kills the fan.

Has my fan supposed to be staying on for 2 minutes and my PCM has just been messed up? Or has this little bypass trick I did discovered something cool!? 😎

 

[CID]

Okay. So final verdict!!!!
Everything works great & I may have just found something cool!!

Now when I shut off the engine, the fan stays running for 2 minutes before shutting down! 🤩

Usually it shuts down with key-off but now it stays running like many have wished for, or installed switches to do..

If I want to shut the fan off instantly; after shutdown, I can switch the key back to the “ON” position and then back to off and it kills the fan.

Has my fan supposed to be staying on for 2 minutes and my PCM has just been messed up? Or has this little bypass trick I did discovered something cool!? 😎

I think you may have discovered something cool, my fan shuts off ~1 second after I turn the key off. I'd like it to stay on til the temp drops but, depending on where the temp sensor is, what's it actually cooling 🤔 once the engine is off?

 

[CostaRicaTalon]

I think you may have discovered something cool, my fan shuts off ~1 second after I turn the key off. I'd like it to stay on til the temp drops but, depending on where the temp sensor is, what's it actually cooling 🤔 once the engine is off?

I think the temp sensor Is up top of the engine somewhere.

A 2 minute cool-down better than no cool down 😎