ONLY blower motor doesn't work, every other function works
 

I'm having an issue where the blower motor just randomly stopped working. The circuit breaker at my feet is still pushed in and good. When I push through all the buttons and change the temperature settings, I can hear the electronics doing their jobs in the dash. However, the blower motor isn't working. Am I supposed to drop the glove box and start messing with the blower motor connections? I'm quite confused as to how just the blower can stop working. Doesn't work on any speed.

I would do that, check the blower and see if it has power, if there is power then the motor is blown, if no power trace back, logicons have a way of playing tricks on you...

The blower motor has a relay, a power transistor and a resistor...any of which may be the culprit in addition to the logicon switch.
The check list for troubleshooting is in the FSM starting on page 15-93.

the small black box on the back of the logicon will also control the blower, its mounted on the logicon but is separate.

I have not heard of this box going bad unless you are like us and were probing wires trying to get a standalone to work the AC.


I know in tracing the system that fucking thing is way more complicated then it needs to be. You would think a fuse or a breaker and that's it, but its a lot more complicated then that.

Like mentioned in a post above, it's either the transistor or one of two relays. The online FSM details how to check out them. BODY ELECTRICAL.

Its very unlikely it's the blower motor. I'd bet on the transistor being blown. It's mounted on the blower housing and if memory serves, ain't touchable with the blower housing in the car.

but the question would be what caused this in the first place?
that needs to be taken into consideration

There are multiple possibilities:

1. blower motor brushes worn, intermittent connection. It is relatively easy to drop the motor; comes straight down from under the right footwell; three bolts, one electrical connector and one rubber cooling air tube. Put the motor on the bench and measure its electrical resistance per the FSM. If that is ok, put 12v on it and see if it runs. If that all passes the motor is probably ok.

2. Heater relay
3. Power transistor (runs the blower motor in all ranges except max)
4. Ex high relay (provides power to the motor in max range only)
5. Wiring/connectors between the blower motor and the logicon
6. Failed fan amp (box on the back of the logicon)
7. Failed logicon

You can check that all of the required voltages are present at the blower assy thru the multipin (16?) connector at the right rear of the blower assy. If the voltages are there, the problem is in the blower assy; if not, it is upstream, i.e. wiring, connectors, fan amp, logicon. Everything you need to check this stuff out is in the FSM.

You can bypass the transistor to see if the blower motor works or not. Its a matter or removing one of the relays and placing it to the side. Then you make a jumper wire and insert it b/t two of the wires in that relays base. If your up to it, I can go to the trouble of remembering which two wires or figuring it out. Been there, done that before several times. Trouble is it will only work on high speed when jumpered.

Personally, I'd refer to the series five heating and A/C, for trouble shooting that problem on your series four.

Was this car a turbo or non turbo car?

Is it now a non RX-7 engine in the car?

When the sllider is put to the FAR right, do you hear the EX-HI relay pull in? Click?

There are two fuse involved. The heater breaker and either the wiper or room fuses. See dwg for what I mean.

I'd pull the EX-HI relay out and set it aside. Then check the red/yellow wire for power with key ON. If it has power, then jumper the red/yelllow to the blue/white. Motor should run.

IF the red/yellow does not have power, then it sounds like the heater relay isn't getting pulled in for unknown reasons. LIke the light green/white wire for its coil isn't getting power from the logicon. OR the relays contacts are not *making* when the relay is pulled in.

The turbo system adds an ignition relay whos purpose is to turn the blower off any time the key is put to Start. Putting the key to start puts a gnd on the ignition relay inside the blower motor housing and interrupts power til the key is returned to ON.

The NON TURBO side of the attached jpg is fugged up and misleading. It shows the WIPER fuse coming from IG1, which we all know is bullshit. It comes from IG2.......meaning if the key is held to start, IG2 fuses do not get power, therefore the blower fan will stop running when the car is being...........started. Common sense thing. IG2 fuses get fed from the igniton switch and ONLY if the switch is in the ON position.

You can tell if the two relays are getting pulled in or not just by putting your hand on the heater relay and with key ON, move the slider to the right at least half way. Should click.

The EX-HI will click if the slider is put faaaaaar right and key ON.

You can tell if the fuses are any good by putting the wipers to On and see if they work or starting the engine and seeing if the meters work (tach, oil, water).

You can see if the transitor is getting varying voltage by putting a meter on the blue orange wire and moving the slider from far left to the far right. The FSM will tell you how much it should vary.

Wow! Thank youfo the spectacular amount of information! O will start lookig through everything.

The chassis is a GXL and all gauges work as well as the wipers.

Like Clokker mentioned above, get the HEATING AND AIRCONDITONING section of the FSM online and download it to your computer. Get the series FIVE which is better than the series four in this area.

My way of doing things is a bit off what the fsm says, but the same in general. Don't be a parts swapper. Figure out which is the bad actor first.

did you ever have the AC working properly with your engine swap?

I have this problem too in an S4 I just re-acquired... I'll check out the S5 FSM and maybe get it figured out this weekend.

Drop the motor and test it with 12v on the bench?

Pull the EX-HI relay and put a jumper wire b/t the Red/Yellow and the Blue/White. IF he fuses are good the blower motor will run if the slider is put to the right. IF it does not run check the RED/YELLOW for batt pwr and if it does have power, the motor is junk. Unlikely the gnd wire went south.

Yes everything was fully functioning with the motor swap. A/C was blowing ice cold. However, car has just been sold. I told the new owner about the car not having any air so hopefully he'll be replacing it.

I didn't have time to check anything this past weekend other than an audible test to hear the clicks of the relays closing when the fan speed slider is operated. I get one click when I move the slider from OFF. So, I can hear the heater relay closing. I don't hear the click when the slider is placed all the way to the right "High" position. So, I'm assuming the EX-HI relay is not closing.

Shouldn't the blower work in low speeds even if the EX-HI relay isn't closing? Or will a bad EX-HI relay cause the blower to not work at any speed?

Thanks... hope to get the meter out this weekend.

The lower speeds won't work if the transistor is blown.

It does sound like the Heater relay is working. Which means to me if the Ex-Hi relay is removed and the wires in its plug are jumpered, the motor will blow IF the slider is put far right.

But your right, if the slider is put to the far right, the extra hi relay should pull in. So why isn't the extra hi pulling in??? Pull the relay out. Get your meter out and see if theres power on the Light green/black wire of the extra hi's coil. Should be there.

If power is on the light green/black, then you need to see if there is a ground coming from the Logicon on the L/Y wire that goes to the extra hi's coil. That's there when the slider is put far right only.

Your missing the light green power or the L/Y ground for that relay. That said.....I'm sure your transistor is shot to heck. Gone bye, bye.

See the jpg attached for the L/Y and light green/black wires going to the extra hi's coil.

Actually you know the light green/black wire is outputting power 'cause the Heater relay also uses the same source of power to pull its relay in.

You can see in the second jpg, that if the transistor is shot, there will be no path to the blower motor.............................unless the extra hi relay is pulled in when the slider is put far right. Ain't happening for you for some reason. Bad ex hi relay or lack of a ground from the logicon when the slider is put far right.

I forget if the extra hi relay is the square one or the round relay. Anyway, if the ex hi is removed, and you jumper the large L/W and R/Y wires with the slider to the right some, the blower will blow if it's any good.

I checked all this out this evening. Pulled the EX-HI relay, had voltage on the LG/B. Jumpered the L/W R/Y... nothing... kind of a hum, and could feel the wire heating up. But that's it. Checked the fuse box for blown fuses... everything is good there. Got out the S5 FSM and got to the step of checking voltage at the blower motor on the L/W terminal. Confirmed voltage there and no voltage on the B terminal. FSM recommends replacing blower motor from what I can tell.

Forgot to mention... I unplugged the blower motor from the harness then just for kicks decided to check the EX-HI relay again. The EX-HI relay is now clicking when the blower motor is unplugged.

Slight Hi-Jack of thread......

My blower motor will click into ex-hi BUT it is really hard to get it to stay there. If I go all the way over to hi it will click into ex-hi but then go right back to "normal" hi. If i give it a slight nudge back twords cold it will go into ex-hi again, but it doesn't allways stay there. Sooooooooooooo any ideas why?

revive! been searching, soldering, and swearing. now im pissed. my fan wasnt working, decided it was my transistor, so i replaced it. if i jumper my wires as stated above it works, the motor itself is good im getting power to my wires and at one point my test light was telling me the transistor was working, as i would slide the fan speed switch up and down and my light would dim/brighten accordingly. but i go to plug everything back in just on the passenger floor before installing, just to make sure it worked.... NOPE! i can get it to work with the EXHI only, and like the guy above me, it doesnt like to stay there. sooooo im stumped unless i blew the new transistor somehow. getting really annoyed at this point. especially because no stores stock the damn transistor. its a few days out via DigiKey. any ideas? thanks

The first thing I'd do is remove the 3 screws that hold the blower fan in place. Drop the fan and run power directly to it to verify it's good.

In my experience, it's common to find water in the fan. Water leaks in from the air duct inside the wiper channel. It sits inside the fan motor and rusts the springs that hold the magnets in place until they fail. The water also freezes in the winter time and prevents the motor from blowing when you want it the most.

If nothing else you'll probably find some leaves and mouse poop if you're lucky.

Did you check the circuit breaker located at the fuse box?