Honda Pilot - Honda Pilot Forums banner

1 - 11 of 11 Posts

·
Registered
Joined
·
30 Posts
Discussion Starter #1
Hello,
My radiator / AC fan occasionally stays on after we turn the car off. I go under the hood and hit the electrical box w/ the relays and it stops. I swapped out the cooling fan relay with a new relay and it still happened again.

Could there be anything else causing this? Or more likely, is the AC fan on a separate relay that I'm missing somehow? Thanks in advance!
 

·
Registered
Joined
·
30 Posts
Discussion Starter #3
That happened to my 2005 Pilot. Turned out there was a slow coolant leak.
Hmm, so the coolant leak caused the fan to stay on after the car was shut off?
My coolant is topped up (although I did add a small amount before a 3500 mile road trip recently)
The fact that it solves itself when I hit the relay box makes me think there's another relay going bad, or a separate relay that I'm missing.
 

·
Registered
Joined
·
1,766 Posts
Could you clarify if it’s the radiator fan (driver side) or the AC fan (passenger side) which remains on?

I have read on here that low coolant level could cause the radiator fan to remain on. If you’ve driven in hot weather that could also be the cause of one or both fans remaining on since there is no longer airflow across the radiator and condenser, once the vehicle is parked, unless one or both fans turn on.

Do the fans eventually turn off or do you have to do something to get them to shut down? I know you mentioned hitting the fuse box but what happens if you don’t do that?
 

·
Registered
Joined
·
30 Posts
Discussion Starter #5
Could you clarify if it’s the radiator fan (driver side) or the AC fan (passenger side) which remains on?

I have read on here that low coolant level could cause the radiator fan to remain on. If you’ve driven in hot weather that could also be the cause of one or both fans remaining on since there is no longer airflow across the radiator and condenser, once the vehicle is parked, unless one or both fans turn on.

Do the fans eventually turn off or do you have to do something to get them to shut down? I know you mentioned hitting the fuse box but what happens if you don’t do that?
Thanks for the help. I'll check next time (it's my wifes car so I don't drive it much) but I feel like it's the passenger side fan. I'm in Minnesota so it's definitely not hot weather.

A month or so ago, before I replaced the cooling fan relay, we came out to a dead battery. I can only assume that the fan kept going and didn't stop. I'll check coolant and which fan is running next time I can and report back.
 

·
Registered
Joined
·
30 Posts
Discussion Starter #6
Update:
My coolant level is fine. In fact, I topped it up recently before a 3500 road trip and the level hasn't changed. It's 10 degrees here in Minnesota so I think I can rule out a coolant leak and the fan running extra because the car is too hot.

Since I previously swapped the cooling fan relay thinking it was bad, I took the old cooling fan relay and used it to replace the AC condenser fan. We'll see if that fixes is.
I just wish there were a way to test this better! It stinks being an intermittent issue. I have a 6 month old and since it's my wifes car, she basically has to open the hood with a 6 month old and hit the relay box when this happens.

If anyone has any ideas or ways to test the relay that would be greatly appreciated!
 

·
Registered
Joined
·
1,766 Posts
If you have a 9v battery, two jumper wires, and an ohm meter you can test the relay. You could also use the Pilot’s battery for this but I’d use the 9v battery to reduce the chance of damaging the Pilot.
1) Remove relay from Pilot
2) Ohm between 30-87 and 30-87a. One should be open (very large resistance), other should be a short (very low resistance)
3) Hook up 9v battery with one terminal to 85 and other terminal to 86. Polarity does not matter. You should hear the relay click as you connect and disconnect one side of the 9v battery.
4) Measure resistance while you connect the battery. With the battery connected it should measure the opposite of step 2

Let me know what you find.
 

·
Registered
Joined
·
13 Posts
Unfortunately, I don't have an instant fix for this issue, but I do have some feedback from my dealership that *might* be helpful when my '08 4WD EX-L Pilot did this. (At the time the Pilot was owned by the previous owner--a close friend of mine.) He had the Pilot at the dealer for the same symptom: Radiator (engine cooling, driver side) fan running continuously. The dealer notes ("RO Notes") state:

"Swapped relay and still ran continuously. Disconnected battery and charged. Performed hard reset on PCM and checked for parasitic draws. Was at 0.015mA. System is operating properly at this time. May need PCM if issues continue."

I don't know how one performs a "hard reset on the PCM", but that might be worth looking in to. Since owning this vehicle (about eight months), I have not had a problem with the fan running continuously. (Knock on wood.) Hopefully you don't need a new PCM. I don't know how much they cost for Pilots, but for Jeeps, they're expensive and a pain to get working properly.

Best of luck to you.
 

·
Registered
Joined
·
125 Posts
I know this thread is a year old, but I thought it was normal for radiator / AC fan to run (occasionally) after car turned off. Maybe you mean your fans never turn off. On our 1991 Civic and 2003 Accord and Pilot, the fan often run after car is turned off if car (and usually weather) was hot.

I found this thread when searching for "radiator fan" as mine is no longer working on 2003 Pilot with almost 250K miles. Mechanic who found this did not think it needed immediate repair unless I'm going to AZ or Las Vegas soon While it is supposed to be 100 here tomorrow and I will be driving to Tahoe, I'm not leaving until evening when temps and traffic should be better.
 

·
Registered
Joined
·
206 Posts
Hello,
My radiator / AC fan occasionally stays on after we turn the car off. I go under the hood and hit the electrical box w/ the relays and it stops. I swapped out the cooling fan relay with a new relay and it still happened again.

Could there be anything else causing this? Or more likely, is the AC fan on a separate relay that I'm missing somehow? Thanks in advance!
A hot engine will cause this. The fan should shut off after a few
 

·
Registered
Joined
·
1,766 Posts
If it were my Pilot, in the middle of the summer, I would get the fan fixed. An overheated engine cost >>> than a radiator fan.
 
1 - 11 of 11 Posts
Top