Check the Power Transistor as well. Usually a resistor fails losing low speeds while high still works

 

Did the Power transistor already. Replaced one and tested the replacement. It passed the tests in the manual.

 

I got the replacement relay finally. The relay was good and I suspect the old relay was good too. It did not solve the problem. As I already mentioned we have already replaced the transistor and it passed all the tests in the manual. Since the transistor passed all its tests I assume the thermal fuse is good.

The relay was very slightly suspicious which is why replaced it. We finally found, I think, the resistor for the blower motor. But it isn’t the coil type that is easy to replace from RockAuto. It is a small black box. I will try to upload pictures. We tested this on the multi-meter and it gives an unstable reading. This has got to be the problem. There is nothing else left I can think of. Can anyone source this part?

 

I cant see the pic, but im thinking you are talking about the fan speed box or whatever its called
It attaches to the logicon. I forgot about that going bad...

 

I see the pic, not what i thought it was. Im not sure what that is, it was on mine but it didnt look important, almost like just a cap or something lol

 

I'm thinking this might be some kind of capacitor but it is not clear from the wiring diagram. It clearly isn't the usual coil resistor. I have emailed a couple of suppliers but with no luck yet. I have also emailed Mazda Canada but have not heard back yet. The dealer who is actually in another city, is no help at all.

Any help identifying this and a supplier would be nice.

This has markings on the end I can read with a magnifying glass as follows:
250v 0.47uF
ECQ-F2474EO7

The Q might be an O but I'm pretty sure its a Q. The first line is obviously the electrical values. I have no idea what the second line means. The "0.47uF" seems like a capacitor designation. I am thinking of wiring up another cap with those values and seeing what happens if I can't replace this part. Any thoughts? Could it make anything worse?

 

not sure if you went over this yet or not, but I have to ask... Your Logicon is working, right?

as long as you use the same values to make a cap it really shouldn't hurt anything. I say give it a shot.
you don't have a junkyard around you do you? maybe go rip out another one and see what happens

 

Logicon seems to work fine. I'll seem what I can do with a junkyard. Does this part show up in any other models. Not too many RX-7s here junked or otherwise.

 

The S5 drawing indicates a condenser..which is basisically a capacitor...it helps to extend the contact life when you switch off a motor which is basically a coil it tends to create a voltage spike. this capacitor helps to reduce the spike and extend contact life on the relays. It will also protect the transistor from voltage spikes. Sorry for adding to such as old post...but as this question was left unanswered.