JesterP

I have an 86, not sure of the specific model. When I slide the slider for the fan speed, I hear a click under the pass dash. It blows zero air from the vents.

Would that mean logicon problem, or the blower motor problem?

Thanks a ton, I need to figure this out....getting cooler out.

J

scathcart

Could be a couple things. Might also want to chec k for continuance on the resistor pack at the back of the blower. I've had those open up a few times and give exactly the problem you describe. Mazda made a revision to them during the S4 run, so perhaps they had problems with them as well?

JesterP

Thanks for the speedy reply. So following that logic....the logicon wouldn't need to be resoldered because it is trying to trip the motor on. OK, now from my reading, is there more than one blower motor? Does the one on the pass side have a specific name? I'm sure I can dig through the tech manual for that.

Thanks again

J

scathcart

No, there's just one blower motor, on the passenger side.
If it were me, I would check pull the blower motor assembly right out and test it on the bench before touching the logicon.
First take direct battery voltager and apply it to the terminals of the motor. If the motor spins, you're golden. If not, replace the motor,
they are known to go bad.
Motor spins... flip the blower assembly over. You'll see a little resitsor pack bolted to the outside of the casing, in the path of the blower outlet. Its in the airflow path to keep the unit cool when we're passing current through it. Take this little pack out, and examine it. See any broken leads? Through your ohmmeter on the leads and check for any O/L's. Any O/L's or broken leads and junk the thing.

Both the motor and the resistor pack OK? Test the logicon. Typically, what I've found though, is its either the motor or the resistors. (Especially resistors on vehicles with solid motor/tranny/suspension mounts).

The motor only takes a couple seconds to pull, and under 5 mins to check. I'd much rather do that than pull the logicon to bench test it.

JesterP

OMG, that's perfect, thanks sooo much. I'll let you know what it was when I check it later this week.



J

kel

Hey Hey,
I fixed this very problem on my '87 TII just tonight. I pulled the fan motor out and threw it on the bench. 12volts across the terminals caused the shaft to jump a bit, but no spinney.
When I took the cover off, it was obvious that the brushes were worn completely away. I found replacements at Ace Hardware for $8 total. Had to shape them down a bit to fit correctly (about 30 min), but now have blasting air where there was a faint breeze before complete stillness.
I'd expect this first on yours too, as there are only so many 'miles' that the brushes can provide and these motors are nearly 20 years old now.

good luck!

- k -

JesterP

Yea, that's a good point, the car is almost 20 yrs old. I'll be yanking it out possibly later today. I'll report my findings. Thanks for taking the time!!

J

johnnyg

Everybody seems to call this thing a "resistor pack", but it's not....it's a power transistor. When I had this problem and got this response, it had me spinning the air box over and over looking for resistors!

JesterP

Hello,

OK, I dropped the fan down, 3 8mm screw bolts. Disconnected the connector plug and the rubber tube. I took it apart and checked things inside, I lightly sanded the metal spring loaded contacts, cleared it all of crap and re-assembled. I sat it upright on the bench, ran 2 wires from my battery charger to the unit, turned on the juice and spinney spinney.

I was stoked. I put it back in the car, and I still get a click under the dash with no spinney spinney/airflow.

Ok, so it's the power transistor..... I can't find it.

Can someone tell me exactly where to find the power transistor? It's not on the assembly that I removed, unless it's microscopic....... I'd like to fix/replace it.

Thanks a ton!

J

JesterP

I think I found the fault. The blower resistor unit. The spring has a 1mm opening and no continuity. Weeee.... now to find one.

Thanks

J

johnnyg

The power transistor mounts on the inside of the airbox so the airflow will keep it cool. There's a 3-connector plug for it on the outside, but you have to take the airbox apart to replace this part.

What blower resistor unit are you referring to? A resistor doesn't have a spring, so I'm confused.

JesterP

Hi,

I found the part listed in a pdf part exploded diagram, "blower motor resistor".

It's little more than a spring between two contacts. It also is in the airflow, but quite a bit easier to get to than the part you are referring to.

http://www.rockauto.com/ref/SMP/SMPD...html?RU281.jpg

Good picture there.

Thanks to all!

J

scathcart

Any length of wire has a resistance, based on its material, total length, and temperature. Its not uncommon to see a resistor made of a coil of wire. They are coiled to allow for a longer length of wire to fit in a small package.
Any coil of wire which conducts current will increase in temperature. Placing the resistor coil in the path of airflow keeps the wire from overheating.

I WAS talking about the blower motor resistor pack, not the transistor.