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Old 06-26-2011, 09:01 AM   #1
wrxmechman
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Unhappy Cabin Blower motor not working at all?

My HVAC blower motor stopped working. Checked all fuses, blower resister and condition of the wiring to the selector switch in the center console. Is there a relay in the car that I missed? Can I swap that relay out with another one that's in the car to check it?
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Old 06-26-2011, 10:52 AM   #2
NemesisWRX
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There is a blower relay attached to the fuse box behind the coin tray of my 03. You can hear it click when you switch the fan from 0 to 1. I'm on my phone so I can't see your car info but if you have an 02-04 (maybe up to 07 even) I would check there. I have been having problems with this relay for a long time. I have replaced it once and it is failing again 2 years later. When I took it off the first time the plug was actually melted slightly. I figured the relay was defective and that was causing my problems but since it started again recently it must be something else. My problems start off by having the blower turn off intermittently and then not turning back on unless the blower is left off for a while. Eventually the blower quits completely. It may be that the relay failed on yours right away instead of dying a slow death like mine. If you're having problems finding which one it is, shoot me a PM with your email address and ill send you a pic of it.
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Old 06-26-2011, 02:01 PM   #3
Cougar4
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Installing a new relay may fix your problem Wrxmechman. The trouble could be with the motor also. You could apply voltage directly to it to see if it works that way.

NemesisWRX
Since you stated that the relay socket is burned this means there is a bad connection which creates excessive heat. You may need to replace the relay socket to fix the problem you are now having. It may also be a good idea to check the current draw of the blower motor as it may be drawing excessive current and can cause this kind of thing to happen over time. Make sure it isn't being slowed down by anything touching the fan.
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Old 06-27-2011, 09:30 PM   #4
wrxmechman
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Thanks for the advice. Does anyone have a pic of this relay. The service manual for an 02 Rex is vague about its exact location. I looked around and I think it is the higher of two round relays that are on the left rear side of the interior fuse panel all the way to the left side of the dash. Is this correct?
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Old 06-27-2011, 10:31 PM   #5
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I think you are correct. You could try swapping them to see if the other one turns the blower on.
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Old 06-27-2011, 11:03 PM   #6
cueball89
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My blower motor relay died on me a few weeks back. It still clicked over when I turned the fan on, but the motor wasn't getting any juice. The relay didn't look oem, so it's potentially the 3rd time the relay has been replaced.

The other round relay can be used to check the blower motor relay.
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Old 06-27-2011, 11:16 PM   #7
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An easy way to trace the problem is to look for power.

With your air system on, check for power to the blower motor, if power is getting to the motor, but it doesn't spin, the blower motor is bad. If there is no power to the blower motor then...

Check power to the blower motor resistor. If power is getting to the resistor but your blower motor still fails to spin, then your blower motor resistor is bad. If there is no power to the blower motor resistor then...

Check power to the blower motor relay. If there is power into the blower motor relay, but no power to either the blower motor resistor or the blower motor itself, then the relay is bad.

If there is no power to your blower motor relay, check your blower motor fuses.

From my experience, it is rare that the blower motor and blower motor resistor go bad, so I would point my finger at the relay. A relay that is going bad will cause intermittent problems.

On my 1993 Legacy, the blower motor relay is located underneath the driver's side dash panel, where all the wires and junk are. If your car is anything like mine it will be on the left side close to the fender. The blower motor relay is just a white color, and it looks similar to the fuel pump relay which is green. The relay will be on a bracket, I just yanked it off the bracket for easier access because it is a tight fit in there.

Get a new relay from the dealer. In my experience, the relays are cheaper at the dealer than at the parts stores for some reason. Replace the relay and check your fuses. (I blew my blower motor fuses after I crossed some 12v wires and blower relay wires with my test light)

So check blower motor > blower motor resistor > blower motor relay > blower motor fuses.

Do the tests, develop a conclusion and report back here and we can furthermore help you out.
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Old 06-28-2011, 01:49 AM   #8
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I think the resistors are located after the blower motor in the circuit so if the resistors are open you will still see voltage at the blower depending on the way you take the measurement. If you take the reading using ground as reference you will see voltage on both sides of the connections to the motor. If you take the reading across the motor connections there will be no voltage seen across them.

Last edited by Cougar4; 06-28-2011 at 03:01 AM.
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Old 06-28-2011, 07:27 AM   #9
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Quote:
Originally Posted by Cougar4 View Post
I think the resistors are located after the blower motor in the circuit so if the resistors are open you will still see voltage at the blower depending on the way you take the measurement. If you take the reading using ground as reference you will see voltage on both sides of the connections to the motor. If you take the reading across the motor connections there will be no voltage seen across them.
The blower motor resistor is before the actual blower motor. The circuit goes as follows:

12 Volt Source -> Heater Blower Fuses -> Blower Motor Relay -> Blower Motor Resistor -> Blower Motor

When testing for power, use a test light, it is a lot easier than having to place your leads on a good ground, place the other one into a prong, and all at the same time, look for a number on your multimeter. With the test light, simply clamp to a good body ground, place the end of the tester into a prong, and look for the light.

If the blower motor resistor is malfunctioning, there is a chance the the blower motor will only receive a full 12v power (Highest blower setting) or 0v power (Off blower setting) This is like this because the blower motor resistor will always receive 12 volts. It's job is to take that 12 volts and reduce it to lower voltages corresponding with the selected fan speed. If the resistor is not doing it's job, it is possible that it will just send 12 volts through, or just be off at 0 volts. So if it is in fact a malfunctioning blower motor resistor, this could be a possible situation.
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Old 06-28-2011, 05:36 PM   #10
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It is interesting your info shows the resistors in line on the power lead before the connection to the motor. My factory service data shows the resistors are tied to the return side of the circuit, after the power connection to the blower motor.
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Old 01-14-2013, 06:12 AM   #11
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Digging this up from the dead - I'm investigating a blower motor not working on my Euro spec MY00 turbo, and can confirm what Cougar says on my car - the resistor pack is on the earth return side of the actual motor. With ignition on you can measure between motor earth wire and ground and read the various resistor values as you change the fan speed switch.

With my problem I have got volts at the blower motor connector with it disconnected, but none with it connected. Motor runs OK directly connected to battery.

I am hoping it is dodgy contacts on the relay itself...

Richard
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Old 01-14-2013, 11:30 AM   #12
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Originally Posted by dowser View Post
With my problem I have got volts at the blower motor connector with it disconnected, but none with it connected. Motor runs OK directly connected to battery.

I am hoping it is dodgy contacts on the relay itself...
From what you say about the voltage readings your hope should be fulfilled. The lack of voltage at the motor while it is connected means there is a high resistance problem upsteam of the motor. The motor and resistors are fairly low resistances in the series circuit so most of the voltage is going to appear across the high resistance, wherever that is at. When you removed the motor from the circuit now the high resistance in the circuit will be the open connection point and you saw the voltage there. The most likely problem is the relay contacts are bad or the connection to it has a problem. A bad connection will usually show signs of burning due to the heat being generated by the excessively high resistance and the current flow through it.

Last edited by Cougar4; 01-14-2013 at 11:36 AM.
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Old 01-14-2013, 01:37 PM   #13
NemesisWRX
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I saw this thread come back up an I just wanted to provide an update on my issues. It turns out that my blower motor was probably the culprit. The last relay I bought didn't fix the issue so I ran through the wires and found that the blower motor had seized. I bought a replacement from a junkyard for $25 and it works better than it ever did before. I did buy one from a newer impreza (06) and had to press the motors out of their plastic housings to swap them as the resistors are different in 05+ models, but it was easy to do. I you are repeatedly frying relays, this may be the issue for you as well. Hope this helps someone out in the future.
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Old 01-28-2013, 11:22 AM   #14
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Nemesis - do you remember how you pressed out the motor? I have an issue with a seized blower motor that needs to be replaced, but I cant see any way to remove/replace the motor other than buying an entire new assembly for $250ish. There has to be a way to get behind the fan piece and pull the motor out, i just cant figure this thing out.
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Old 04-09-2013, 06:08 PM   #15
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I have an '08 and the blower motor stopped. If I bypass the relay the fan works (all four settings) but the control contacts for the relay are only getting about .96 volts. Doesn't seem like enough voltage to close the circuit. Is this a similar problem? I've not found anything exactly like this using the search, and I would have started a new thread, but the forum robots seem to think I'm a spammer until I have posted three times. Here's post #1... any help really appreciated, not trying to be a rule breaker.

Thanks
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Old 04-09-2013, 06:11 PM   #16
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P.S. Also forgot to mention that I haven't checked the resistor itself. I'm making the assumption that It works based on all fan speeds working properly with the relay bypassed. Any chance the resistor supplies the control voltage to the relay too?
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Old 04-09-2013, 06:15 PM   #17
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P.P.S. Also tried swapping in a brand new relay. No change, and both old and new relays show identical resistance across the contacts. (there went 20 bucks...)
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Old 04-09-2013, 08:27 PM   #18
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The power for the relay coil most likely comes from a different fused circuit than the blower motor power so if you haven't made sure all the fuses in the dash panel have power getting through them then do that. The coil needs about 12 volts to work like it should. The relay coil is most likely turned on by making a ground connection through the speed switch.
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Old 04-10-2013, 12:44 AM   #19
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Thanks. I will update if (when) I figure it out. Rechecking all fuses. Also curious... rear defrost stopped working same time as the blower. Doesn't work even with relay bypassed.
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Old 04-10-2013, 11:09 AM   #20
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Well that could mean there is a blown fuse that is used for that area also. Fuses supply power to multiple circuits. If you don't find a bad fuse in the dash panel then check the ones under the hood also. You need to verify power is getting to all the fuses using a test light probe and not just look at them.
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Old 04-13-2013, 10:38 PM   #21
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Yeahoner, I'm having a similar problem to you in my '04, but I'm a few steps behind you. Not exactly sure where the blower relay is--I think it is the top of two round relays to the left of my cabin fuse box. If that's it, then I don't think mine is getting power. There is a four prong female connector that goes to it, and I'm only getting continuity between two of those contacts. I'm assuming it should be 12 volts across the other two of those? Either way, checked my circuit breakers, and they all look good. Am I messing something up there? Thanks.
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Old 04-14-2013, 07:12 AM   #22
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First verify that fuses 1 and 2 in the dash fuse panel have power on both sides of them by checking the slits on top of the fuses using a test light probe or meter. When checking the relay there should be power on 3 of the 4 leads when the blower is supposed to be on. The fourth lead will be tied to ground when activated.
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Old 04-14-2013, 12:46 PM   #23
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Getting power to the fuses. Getting 12 V, 12 V, 6 V, and no continuity between the four terminals that go to the top relay. Is that 6 V correct? Getting 12 V, 12 V, and no continuity for the other two on the bottom relay.

Last edited by recon_six; 04-14-2013 at 02:03 PM.
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Old 04-14-2013, 06:40 PM   #24
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Keep us updated.
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Old 04-15-2013, 10:06 AM   #25
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Quote:
Originally Posted by recon_six View Post
Getting power to the fuses. Getting 12 V, 12 V, 6 V, and no continuity between the four terminals that go to the top relay. Is that 6 V correct? Getting 12 V, 12 V, and no continuity for the other two on the bottom relay.
You ask if the 6 volt reading is correct and the answer is no, that isn't correct. Vehicles use a 12 volt power system so something ahead of the fuse is bad. I need to know which fuse had the 6 volts on it to be able to determine where to check for the problem. There is most likely another fuse involved with the circuit. When you checked the voltages I assume you checked both sides of the fuses to make sure they were okay.

A common relay has four connections. The relay coil uses two wires which are normally smaller in size than the other two wires. In a lot of cases, one side of the relay coil is usually tied to a power source and the other side of the coil is usually tied to a switched ground connection to control the relay action. Sometimes the hot side of the coil has the switch control instead of the return side depending on the design of the circuit. The other two wires are usually larger in size and they are tied to the switched contacts of the relay which normally passes power to the load of the circuit. One of those wires is usually tied to a fused power source and the other wire ties to the load of the circuit. When the relay is ON then both of the wires should have 12 volts on them. When the relay is OFF only one of the two wires will have power going to it since the connection is now broken or in an open condition.
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