So my heater blower fan isn't working. I have tried to make sense of the fsm, but haven't been able to. I have also pulled up a few threads and tried to make sense of them with no luck as well. So from my troubleshooting this is what I have found out. First of all I have an 88 RX7 T2. I pulled the fan and it turns when I connect it to the battery. I then notice that the 2 wires that connect the fan have melted together some. So I separate them and wrap them up. I then check voltage at the plug and get a full 12V when the fan swtich is all the way on. It also changes voltage as it goes all the way up. I plug it back in and nothing. So i unhook the fan again and use wires to verify connectivity and as soon as I connect the 12 v to the fan it drops to 0 volt. Any ideas? It is making no sense to me.

 

There are 2 relays in the blower system iirc, theres one for high speed (full blast) and one to help kick it in. Theres also a variable resistor on the blower housing that can go bad

Just fyi, if one of the relays is bad, prepare yourself, they are pricey suckers new

 

Through a little more searching I finally found a diagram that makes a little more sense which must be from an S5 FSM. I am going out on a limb and believe I have a bad ground that is on the B wire on the plug that connects the blower motor. Hopefully I can find the S5 FSM when I get home to download it as I just pulled up a jpg that HAILERS had posted in another post. I did however print it out though.

 

Yes follow the s5 FSM, MUCH more descriptive

 

Well I still haven't solved the mystery yet. I get voltage on the 12v on the 1 wire and 0 volt on the other wire and the manual says to replace the blower motor. I bought a new blower motor in still doesn't work. It just clicks.

 

Search. There's a thread about this. Thermo resistor. Find it, replace it.

 

I have searched threads as I will say again. I just searched "Thermo Resistor" and I see no threads pertaining to this issue. I'll keep stumbling on when I get a chance. I will post back when I get to the bottom of the issue.

 

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/only-blower-motor-doesnt-work-every-other-function-works-864152/page3/ first thing that pops up when searching...

 

I have already found that thread. I went through the guide that Hailers posted and it failed on step 3 which states replace blower motor. I replaced and same result. I don't see where it tells me to replace the transistor. For one my voltage changes as I move the fan speed up varying the voltage. So i figured that was good. Thanks for the link though.

 

Did you do the following and if so what happened?

"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/yellow to the blue/white. Motor should run."

 

posting for subscription. I have a blower motor that intermittently works.

 

So I hate these types of fixes where the fix is not exactly clear. So i found I had blown a fuse from jumpering the wrong item before. So I replaced that fuse then started to troubleshoot again. I pulled the relay again and checked voltage on the blue/white and red/yellow also had voltage. 1 of them had 12 volts and the other only 10 with car not running. So i wire up my fan then plug it in and it starts blowing. I was like wtf? So I turned the key to off on the car and wired it all up and put it back together and the fan worked but wasn't blowing much air. I turned key off again and swapped my wires on the fan and hooked back up and the fan was blowing harder then ever like a new fan should. Again thanks for the replys. I just hope the gremlin doesn't come back. But at least I feel a little more familiar with the fan now.

Shane

 

I know this is old but I figred I would bump to see if you got it fixed.

My heat worked great till yesterday morning when the blower stopped working. All heater functions still work but no blower at any speed, iv been told its probably the blower motor relay. Someone told me to swap the wiper motor relay with the blower but to be honest I don't know where any of them are located.

 

Yes I got it fixed. It was a bad blower. I had also popped a fuse as well when troubleshooting and when I replaced that too I was good to go.The blower fan would spin when I manually applied power with a battery after I removed it. However it was still not any good. I bought a replacement for like $30 I believe and slapped it in and I was good to go.

 

 

you may have got it fixed by now but definitely check the resistor for the blower motor, in my 87 mazda b2000 this was always the issue when my blower stopped working. mine was located behind the glove box and takes 2 screws to put a new one in, im guessing its the same for the 87 rx7

 

 

The transistor is on the blower motor unit, attached to the metal heat sink within the fan box underneath the dash. It was intended to be swapped out as an entire unit, but if you have a soldering iron and some thermal paste, you can swap out the transistor and keep the heatsink assembly. We have some threads on how to do this. There is a small thermal resistor attached to the transistor within this assembly as well. Any other resistors in the circuit would be in the fan amp located in the A/C control unit.