No main fan or AC fan - Subaru Outback

hiker88 · 07-29-2010, 08:32 PM

Hi

I have a 2006 Outback 2.5i. For some time this summer I noticed the AC has not been as good as it should be.

Today I noticed the radiator temp would go above normal if AC was on.

I bought a recharge kit with gauge and the pressure was low. I recharged to normal level based on todays ambient temp.

After recharging the air still was not colder. I noticed that the AC pulley is engaging, but neither of my fans come on at any time. On my Kia, both fans come on whenever the AC is on so I suspect something is up with a relay or something.

Can someone give me some basic troubleshooting steps? I have a mult meter with basic understanding of how it works. The issue is I see several relays either labeled main fan, AC fan, main fan2, sub fan relay etc. I don't know where to start.

Thank you for your help.

hiker88 · 07-29-2010, 11:39 PM

I think what I was calling the AC fan is actually called the sub fan (the one on the passenger side). I've been reading some other stuff on the forum so that helped there.

Any way, here is what I have tried so far tonight. I think the AC relay and the sub fan relay are good. The current AC relay makes the AC pulley come on, if I take it out, no AC pulley. The sub fan and AC relay are the same. I switched them and the AC pulley still works.

I ohmed both 25amp main fan fuses (the ones in the engine compartment) and got a tone from my multimeter so I think they are good.

I tried hooking 12 vdc directly to the main fan plug and the fan did not come on. It seems like it should, but then that would mean the other fan (sub) must be bad too? I have not tried to get to the sub fan yet.

So I think this is where I am at
I have two bad fans - seems kind of unlikely
I'm incorrectly trying to apply power to the main fan - knowing me could be likely
The main fan2 relay could be bad - I don't know how to test it
The main fan relay could be bad - I don't know how to test that either.

Any thoughts? My resident mechanic (my dad) is at the EAA venture in Wisconsin right now so I'm kind of stuck.

halfapie · 07-30-2010, 02:23 AM

how did you exactly test your relays? even if you get a tone from your multimeter, it could still be bad.

Measure the resistance you get when you apply 12 volts across the other two contacts. It should be a very small number, and it should be the same ohms when you try it multiple times.

ETC · 07-30-2010, 04:55 AM

To check the fan plug for voltage, unplug it, use a meter or test light on the plug that goes away from the fan [not the fan itself]. Turn the AC on and test each plug ... any juice there ? [ground the meter to the chassis and test both pins in the plug for power] if there is power at the plug, test the fans.

To check the fans- Run a jumper wire from the Pos + side of the battery to one pin [or slot, forget which way it's oriented] on the fan side of the plug. Run another from the Neg - side of the battery to the other. The fan should run no matter which way you touch the pins, if it's backward, the fan will just run backward. careful, that is full battery amperage you're playing with ... ground the hot and you are essentially arc welding ;]

If the fans don't run with direct voltage from the battery, they are no good. It is rare to have both go out at once and it is pretty new for them to fail but, stranger things have happened.

If there is no power at the plug, check all the fuses with a meter or test light with the ign in the on position. You should be hot on both sides of the fuses [most fuses have a little metal nub on the top, both sides]. if all fuses are good, check relays.

How to test a relay

YouTube - Auto Repair & Mechanics : How to Test a Car Relay

This may seem odd but, use the lid of the fuse box and check that the relays are in the correct spot. Again, I've seen some strange things happen after cars are serviced.

Good luck, let us know what happens

hiker88 · 07-30-2010, 06:07 AM

I actually ohmed the two fuses - not the relays. I will try checking the fans, then the relays.

In response to:

how did you exactly test your relays? even if you get a tone from your multimeter, it could still be bad.

Measure the resistance you get when you apply 12 volts across the other two contacts. It should be a very small number, and it should be the same ohms when you try it multiple times.

plain OM · 07-30-2010, 09:36 AM

Quote:

noticed that the AC pulley is engaging, but neither of my fans come on at any time.

Fundamentally, both fans should be running whenever the compressor is engaged (as with the Kia). However, they might be running at either slow or high speed, depending on engine temperature, vehicle speed, and compressor load. This is controlled by the ECM by switching the related relays (main fan 1, main fan 2 and sub-fan) as noted in the attached (marked) diagram.

When the engine is relatively cool, at idle, and the compressor is engaged, the fans should be running at the slower speed. Because they are in series, a problem in one fan circuit (e.g open fan connector) can prevent both from working. But if the engine temperature is above normal, both fans should be running at the higher speed (whether or not the AC is on), and even if one fan circuit is defective, the other one should be running.

It's fairly easy to set up the first condition (cool engine with AC on), but what about the second? Is neither fan running when the temp gauge is above normal and the compressor clutch is engaged? If one of the fans is running in the latter instance, this will isolate the problem to the other fan circuit.

While it's not likely that both motors, or a pair of relays, or more than one fuse, will have failed at the same time, it is possible for this to have occured in stages without it being noticed. All the relevant fuses should be checked by confirming actual resistance rather than the "tone" indicator. (Use the lowest resistance range, and make sure that the resistance reading for the fuse, when removed from the socket, is far less than one Ohm. This is because many digital Ohmmeters will give a "tone" indicating continuity anywhere between zero and up to 200 Ohms, whereas a fuse with even 10 Ohms of resistance can indicate a defect.)

From the diagram it looks as if main fan relay 1 and the sub-fan relay (and, as you noted the AC relay) appear to all be the same. So you might be able to verify the main fan relay by putting it in the AC relay position and seeing if the compressor clutch engages.

The main fan relay 2 is a different relay altogether and would have to be checked independently.

Because the ground connection (in the diagram, below the main fan motor) is common to both fans at both speeds, make sure that it is good. With the engine off, at either fan connector (the one from the harness) check that the resistance at pin 1 is less than 5 Ohms to a good chassis ground point.

hiker88 · 07-30-2010, 10:12 AM

I haven't been able to get the fans to come on in any condition. Last night I got the radiator temperature up quite a bit and no fans came on. I did not let it get into the red, but I have a transmission temp gauge and it was up to about 190.

Interesting note, I tried to remove the main fan2 relay to check it and it pulled apart when I was removing it. I don't know the constant AC compressor cycling might have overheated the relay. If it wasn't the original problem - it's a problem now.

I'm going to go see if the dealer has the main fan2 relay and I'm just going to buy some 25a main fuses and replace them instead of messing around with them.

If none of that fixes it, I think I am down to the main fan relay or both fans being bad.

More to follow.

plain OM · 07-30-2010, 02:01 PM

If my understanding of the way the circuit works is correct, even with main fan relay 2 removed, when the engine temp is above normal, main fan relay 1 should have activated (i.e. the ECM is setting the fans on high speed), turning the main fan on, while the sub-fan would remain off due to the absent main fan relay 2. (A bad main fan 2 relay would affect the slow speed of both fans due to its role in the series connection, and the high speed of the sub-fan due to its routing the ground for the sub-fan, but not the high speed of the main fan.)

Looking at the main fan relay1, if it is bad (or, for that matter, removed), it wouldn't affect the slow speed operation, nor the high speed function of the sub-fan.

Similarly, if one fuse is out, it might affect one aspect of the fan operations, but not both. It would require at least two fuses, one in each high speed circuit, to be open for there to be no fan operation at all.

So while the wiring circuit for the fans appears overly complex, in some ways it has built in failsafes and possible diagnostic indicators.

Because neither fan comes on even when the engine temp is above normal, it has to be something common to both the slow and high speed arrangements. In this regard, there's still the common ground that should to be verified, along with the connections to the motors (connect and disconnect a few times and see if that changes anything), and the motors themselves.

In regard to the motors, have you tried manually spinning the fans (ignition OFF) just to get the motor rotors into a different position? Also, it should be possible to measure the resistance across the motors at their two-pin connectors. The resistance should be low (if the motors are open circuit, the resistance reading will be high) and when the fan is manually turned, the Ohmmeter reading should jump around (due to magnetically induced voltages).

hiker88 · 07-30-2010, 02:47 PM

Well,

It's starting to look more and more like the fans. My local dealer had none of the relays, but a dealer about 20 miles away had the main fan, and main fan2 relay. Since I was all the way over there, I bought them both and it didn't make a difference.

I changed both 25a fuses as well. Same deal, compressor is on, but no fans. I'm heading over to my dad's now becuase his garage is better equipped if it ends up being the fans I need to change...

hiker88 · 07-30-2010, 03:27 PM

I can't get either fan to run when applying 12 vdc to them. I'm checking around for parts now. Is there a good thread here for swapping the fans out?

07-29-2010, 08:32 PM	#1 (permalink)
hiker88 Registered User Join Date: May 2008 Location: Belgrade, Maine Car: 2006 Outback 2.5i Posts: 46 Feedback Score: 0 reviews	No main fan or AC fan Hi I have a 2006 Outback 2.5i. For some time this summer I noticed the AC has not been as good as it should be. Today I noticed the radiator temp would go above normal if AC was on. I bought a recharge kit with gauge and the pressure was low. I recharged to normal level based on todays ambient temp. After recharging the air still was not colder. I noticed that the AC pulley is engaging, but neither of my fans come on at any time. On my Kia, both fans come on whenever the AC is on so I suspect something is up with a relay or something. Can someone give me some basic troubleshooting steps? I have a mult meter with basic understanding of how it works. The issue is I see several relays either labeled main fan, AC fan, main fan2, sub fan relay etc. I don't know where to start. Thank you for your help.

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07-29-2010, 11:39 PM	#2 (permalink)
hiker88 Registered User Join Date: May 2008 Location: Belgrade, Maine Car: 2006 Outback 2.5i Posts: 46 Feedback Score: 0 reviews	I think what I was calling the AC fan is actually called the sub fan (the one on the passenger side). I've been reading some other stuff on the forum so that helped there. Any way, here is what I have tried so far tonight. I think the AC relay and the sub fan relay are good. The current AC relay makes the AC pulley come on, if I take it out, no AC pulley. The sub fan and AC relay are the same. I switched them and the AC pulley still works. I ohmed both 25amp main fan fuses (the ones in the engine compartment) and got a tone from my multimeter so I think they are good. I tried hooking 12 vdc directly to the main fan plug and the fan did not come on. It seems like it should, but then that would mean the other fan (sub) must be bad too? I have not tried to get to the sub fan yet. So I think this is where I am at I have two bad fans - seems kind of unlikely I'm incorrectly trying to apply power to the main fan - knowing me could be likely The main fan2 relay could be bad - I don't know how to test it The main fan relay could be bad - I don't know how to test that either. Any thoughts? My resident mechanic (my dad) is at the EAA venture in Wisconsin right now so I'm kind of stuck.

07-30-2010, 02:23 AM	#3 (permalink)
halfapie Registered User Join Date: Jan 2010 Location: Colorado Springs Car: 05 XT limited Posts: 104 Feedback Score: 0 reviews	how did you exactly test your relays? even if you get a tone from your multimeter, it could still be bad. Measure the resistance you get when you apply 12 volts across the other two contacts. It should be a very small number, and it should be the same ohms when you try it multiple times.

07-30-2010, 06:07 AM	#5 (permalink)
hiker88 Registered User Join Date: May 2008 Location: Belgrade, Maine Car: 2006 Outback 2.5i Posts: 46 Feedback Score: 0 reviews	I actually ohmed the two fuses - not the relays. I will try checking the fans, then the relays. In response to: how did you exactly test your relays? even if you get a tone from your multimeter, it could still be bad. Measure the resistance you get when you apply 12 volts across the other two contacts. It should be a very small number, and it should be the same ohms when you try it multiple times.

07-30-2010, 10:12 AM	#7 (permalink)
hiker88 Registered User Join Date: May 2008 Location: Belgrade, Maine Car: 2006 Outback 2.5i Posts: 46 Feedback Score: 0 reviews	I haven't been able to get the fans to come on in any condition. Last night I got the radiator temperature up quite a bit and no fans came on. I did not let it get into the red, but I have a transmission temp gauge and it was up to about 190. Interesting note, I tried to remove the main fan2 relay to check it and it pulled apart when I was removing it. I don't know the constant AC compressor cycling might have overheated the relay. If it wasn't the original problem - it's a problem now. I'm going to go see if the dealer has the main fan2 relay and I'm just going to buy some 25a main fuses and replace them instead of messing around with them. If none of that fixes it, I think I am down to the main fan relay or both fans being bad. More to follow.

07-30-2010, 02:01 PM	#8 (permalink)
plain OM Registered User Join Date: Jun 2006 Location: Nepean ON Canada Car: 07 OBW 2.5i Touring (SE) D-4AT Posts: 1,821 Feedback Score: 0 reviews	If my understanding of the way the circuit works is correct, even with main fan relay 2 removed, when the engine temp is above normal, main fan relay 1 should have activated (i.e. the ECM is setting the fans on high speed), turning the main fan on, while the sub-fan would remain off due to the absent main fan relay 2. (A bad main fan 2 relay would affect the slow speed of both fans due to its role in the series connection, and the high speed of the sub-fan due to its routing the ground for the sub-fan, but not the high speed of the main fan.) Looking at the main fan relay1, if it is bad (or, for that matter, removed), it wouldn't affect the slow speed operation, nor the high speed function of the sub-fan. Similarly, if one fuse is out, it might affect one aspect of the fan operations, but not both. It would require at least two fuses, one in each high speed circuit, to be open for there to be no fan operation at all. So while the wiring circuit for the fans appears overly complex, in some ways it has built in failsafes and possible diagnostic indicators. Because neither fan comes on even when the engine temp is above normal, it has to be something common to both the slow and high speed arrangements. In this regard, there's still the common ground that should to be verified, along with the connections to the motors (connect and disconnect a few times and see if that changes anything), and the motors themselves. In regard to the motors, have you tried manually spinning the fans (ignition OFF) just to get the motor rotors into a different position? Also, it should be possible to measure the resistance across the motors at their two-pin connectors. The resistance should be low (if the motors are open circuit, the resistance reading will be high) and when the fan is manually turned, the Ohmmeter reading should jump around (due to magnetically induced voltages).

07-30-2010, 02:47 PM	#9 (permalink)
hiker88 Registered User Join Date: May 2008 Location: Belgrade, Maine Car: 2006 Outback 2.5i Posts: 46 Feedback Score: 0 reviews	Well, It's starting to look more and more like the fans. My local dealer had none of the relays, but a dealer about 20 miles away had the main fan, and main fan2 relay. Since I was all the way over there, I bought them both and it didn't make a difference. I changed both 25a fuses as well. Same deal, compressor is on, but no fans. I'm heading over to my dad's now becuase his garage is better equipped if it ends up being the fans I need to change...

07-30-2010, 03:27 PM	#10 (permalink)
hiker88 Registered User Join Date: May 2008 Location: Belgrade, Maine Car: 2006 Outback 2.5i Posts: 46 Feedback Score: 0 reviews	I can't get either fan to run when applying 12 vdc to them. I'm checking around for parts now. Is there a good thread here for swapping the fans out?