[Dad’s Garage]

Condenser fan (pass. side) is bad. I’ve determined that. Put 12v directly to it, no response. Got radiator fan to kick on with A/C control turned on. Let it idle in driveway yesterday with A/C off and radiator fan would not turn on when engine got to running temp.

I jumped the fan switch/ temp sensor which is screwed into the radiator and got no response from either fan but the radiator fan (driver side) would run with A/C control on. My understanding is that has nothing to do with the fan switch which is triggered by engine coolant temperature alone.

Am I supposed to get a response from both fans with the switch/ temp sensor jumped?
Thanks! Trying to determine if that switch in the radiator is also bad. Already ordered the condenser fan.

 

[Carbuff2]

I know (from doing the Idle Learn Procedure) that the EFFICIENT GEN2 engine would not turn on, even after idling 30 minutes.

When idling in cold temps, the coolant temp actually goes down. (This from an OBDII scanner)

Wisdom here is to warm up the engine for 15 minutes, then turn off to let everything heat-soak. THEN see.

 

[Dad’s Garage]

This was part of my issue; the temp would not climb even with the fan not engaging but did appear that it was at “normal operating temp.”

 

[Carbuff2]

did appear that it was at “normal operating temp.”

The dash gauge is 'dampened' around the normal area. It is not a good indicator of actual temps.

With an OBDII, you will see where the engine coolant sensor (that the ECU uses) is indicating...

I think it needs to go over ~220F. to turn on the fans, without A/C engaged. Not sure tho', its been years since I monitored....

 

[Dad’s Garage]

So do you know if both fans should engage when bypassing the switch screwed into radiator? Neither came on when bypassed.

 

[Avisitor]

Sorry to interrupt.
According to the schematic, the radiator fan switch has one side to the ECM (fan control)
The other side of the switch goes to ground.
If you short or bypass the switch then the ECM should tell the radiator fan to turn on
The condenser fan will not turn on necessarily
So if it does not turn on the fan then either the wire going to ground is faulty
(Usually it is the ground point itself that needs a little cleaning)
Or the wire going to the ECM is open
Of course this is based on the fan turning on when the AC is turned on

 

[Carbuff2]

The radiator switch switch goes to the dash gauge

The fans (no A/C) turn on by way of the cylinder head temp sensor.

 

[RxRC]

I know (from doing the Idle Learn Procedure) that the EFFICIENT GEN2 engine would not turn on, even after idling 30 minutes.
When idling in cold temps, the coolant temp actually goes down. (This from an OBDII scanner)

Right. I've had temp issues when idling at below zero temps.

 

[Dad’s Garage]

Sorry to interrupt.
According to the schematic, the radiator fan switch has one side to the ECM (fan control)
The other side of the switch goes to ground.
If you short or bypass the switch then the ECM should tell the radiator fan to turn on
The condenser fan will not turn on necessarily
So if it does not turn on the fan then either the wire going to ground is faulty
(Usually it is the ground point itself that needs a little cleaning)
Or the wire going to the ECM is open
Of course this is based on the fan turning on when the AC is turned on

No need to apologize. I asked because I’m in need of help to figure this out. I appreciate it.

Here’s what I’ve figured out. The radiator fan will run intermittently with the AC on. With AC off, radiator fan will not turn even when engine temp climbs. I just got it to climb quite a bit (3/4 of the way to the “H”) by driving at idle speed in a parking lot. The engine will not cool until you get some speed going and cold air hitting the radiator.
So the radiator fan is not bad, it turns on and off with the AC on. If my relays and fuses are good does this seem to indicate failure of the temp switch in the block ?

 

[ajchien]

From what I understand, you jumped the electrical connector down at the radiator/thermo fan switch and got no response from your working radiator fan. I am curious if you have power and ground at their respective pins down at the radiator/thermo fan switch connector?

 

[Dad’s Garage]

From what I understand, you jumped the electrical connector down at the radiator/thermo fan switch and got no response from your working radiator fan. I am curious if you have power and ground at their respective pins down at the radiator/thermo fan switch connector?

Correct. Jumped it, no response from working radiator fan.
Without a meter to test (and no idea how to operate one but it’s on the list of stuff to learn) where would I go next? To the box containing the relays?

 

[ajchien]

Correct. Jumped it, no response from working radiator fan.
Without a meter to test (and no idea how to operate one but it’s on the list of stuff to learn) where would I go next? To the box containing the relays?

edited post.


I went to the service manual sticky at the top of the Gen 2 forum. I looked up the circuit diagram for the Gen 2 cooling fans. The service manual in the sticky is for a CRV from Australia I think. It’s not the USDM service manual. However, I believe the overall design is the same. Exact fuse numbers or wire colors could potentially differ. i would advise finding a USDM diagram to be absolutely sure if it comes down to details like that.

Since you applied power (and I presume you applied ground also) to the condenser fan, and found that it did not work, I colored that in RED.

Since you turned in the AC and found that the radiator fan works, I colored that BLUE.

Since you jumped the radiator fan switch, and did not get any fan activation, I colored that GREEN.

There is no color on the things you have not yet tested.

 

[Avisitor]

Here’s what I’ve figured out. The radiator fan will run intermittently with the AC on. With AC off, radiator fan will not turn even when engine temp climbs. I just got it to climb quite a bit (3/4 of the way to the “H”) by driving at idle speed in a parking lot. The engine will not cool until you get some speed going and cold air hitting the radiator.
So the radiator fan is not bad, it turns on and off with the AC on. If my relays and fuses are good does this seem to indicate failure of the temp switch in the block ?

The radiator switch is not faulty since when you jump or bypass the switch
The fan still does not turn on.
On the other schematic it is easy to see that either the switch tells the fan to turn on
Or the ECM will tell the fan to turn on.
Each would provide a ground. The AC button seems to tell the ECM to go to ground
Thus turning on the fan. As was mentioned, the ground is probably corroded.
Where that ground point is? I do not know.
Jump the switch and go to ground and the fan should turn on.

 

[Dad’s Garage]

The radiator switch is not faulty since when you jump or bypass the switch
The fan still does not turn on.
On the other schematic it is easy to see that either the switch tells the fan to turn on
Or the ECM will tell the fan to turn on.
Each would provide a ground. The AC button seems to tell the ECM to tell it to go to ground
Thus turning on the fan. As was mentioned, the ground is probably corroded.
Where that ground point is? I do not know.
Jump the switch and go to ground and the fan should turn on.

I am grateful for the amount of effort you poured into this for me. Thank you. I have a much better understanding now given the schematic and the color coding. I have been looking at the stickies as well.
I am trying to get this car ready for my 16 year old daughter and thanks to all for the assist in getting this thing on the road in better shape.

 

[Card1]

Condenser fan (pass. side) is bad. I’ve determined that. Put 12v directly to it, no response. Got radiator fan to kick on with A/C control turned on. Let it idle in driveway yesterday with A/C off and radiator fan would not turn on when engine got to running temp.

I jumped the fan switch/ temp sensor which is screwed into the radiator and got no response from either fan but the radiator fan (driver side) would run with A/C control on. My understanding is that has nothing to do with the fan switch which is triggered by engine coolant temperature alone.

Am I supposed to get a response from both fans with the switch/ temp sensor jumped?
Thanks! Trying to determine if that switch in the radiator is also bad. Already ordered the condenser fan.

The condensor fans aren't controlled by the fan or radiator temp switch, but by the air conditioner switch, or if you have automatic cabin temperature control by that system.

 

[tglenn]

Condenser fan (pass. side) is bad. I’ve determined that. Put 12v directly to it, no response. Got radiator fan to kick on with A/C control turned on. Let it idle in driveway yesterday with A/C off and radiator fan would not turn on when engine got to running temp.

I jumped the fan switch/ temp sensor which is screwed into the radiator and got no response from either fan but the radiator fan (driver side) would run with A/C control on. My understanding is that has nothing to do with the fan switch which is triggered by engine coolant temperature alone.

Am I supposed to get a response from both fans with the switch/ temp sensor jumped?
Thanks! Trying to determine if that switch in the radiator is also bad. Already ordered the condenser fan.

2bd fan only kicks in with compressor.

 

[Garfy]

Condenser fan (pass. side) is bad. I’ve determined that. Put 12v directly to it, no response. Got radiator fan to kick on with A/C control turned on. Let it idle in driveway yesterday with A/C off and radiator fan would not turn on when engine got to running temp.

I jumped the fan switch/ temp sensor which is screwed into the radiator and got no response from either fan but the radiator fan (driver side) would run with A/C control on. My understanding is that has nothing to do with the fan switch which is triggered by engine coolant temperature alone.

Am I supposed to get a response from both fans with the switch/ temp sensor jumped?
Thanks! Trying to determine if that switch in the radiator is also bad. Already ordered the condenser fan.

Without knowing what year your CR-V is makes giving an answer difficult. However, in most Hondas despite the fans being called "radiator" and "condenser" fans, BOTH of them usually cycle on and off together, whether triggered by coolant temperature or by the A/C being on (in which case the fans cycle on and off with the compressor clutch going on and off). It's very common for the condenser fan motor to fail (that's the flat "pancake" motor); they tend to fail at least twice as often as the radiator fan motor which seems to built better.

 

[Dad’s Garage]

Without knowing what year your CR-V is makes giving an answer difficult. However, in most Hondas despite the fans being called "radiator" and "condenser" fans, BOTH of them usually cycle on and off together, whether triggered by coolant temperature or by the A/C being on (in which case the fans cycle on and off with the compressor clutch going on and off). It's very common for the condenser fan motor to fail (that's the flat "pancake" motor); they tend to fail at least twice as often as the radiator fan motor which seems to built better.

Yep that is definitely important; it’s a 2002.

 

[Dad’s Garage]

According to the shop where I took it after failing to figure it out; despite the radiator fan kicking on with 12v of direct power applied, it was defective.

According to them, it now runs as designed. All other components checked ok. They did an electrical test of the entire circuit. The guy explained to me why the fan would still kick on despite being bad (which I cannot regurgitate) but said that the fan itself was the component with the open circuit.

 

[Avisitor]

Yeah, that doesn't make sense to me either.
If you put power to the connector of the fan and it works then how is it open circuited?
The other thing I would like to see if you ohm out the fan. Is it open or not?

Well, is it really fixed?