Blower Motor Problem

[bclaremont]

1988 RX-7 Convertible

I have a problem with the Heat/AC blower motor.  The motor will only come on when the ignition is switched on with the fan slider control in the max position.  If the fan is speed is lowered, the fan quits and will not come back on until the slider is set to max and the ignition is switched off and back on.


I took the blower motor apart and checked the brushes. They are fine. I also tried a new motor and had the same problem.

I tested some more and found the following:

With the blower motor disconnected and an electrical tester in its place, everything appears to work normally. As you push the slider control from left to right current starts to flow and builds up to max output. I checked this running through the blower\'s ground wire and connected directly to a chassis ground. Same results both ways.

With the blower connected and electrical probes clipped into the power and ground tabs on the motor:

> If I active the slider from off I get nothing. No current flow at all.

> If I set the slider at max, then switch on the ignition, the blower comes on and I show current flow. As soon as I slide off of max the blower shuts down and current flow stops. It will not reactivate if the slider is pushed back to max. Again, I checked this using both the blower ground wire and a chassis ground with the same results.

I found the high and low speed relays. Starting from the off position on the slider with the ignition on, If the blower motor is plugged in, only the high speed relay clicks when the slider hits the max position. If the motor in unplugged, both relays click.

If the resistor in the relay is blown, should I get full current or no current across it?

Anybody run across this problem or know how to fix it?

Thanks!

[clive]

Hi And Welcome ,

Had the same problem with my Gen 2 and l put as a "temporary" fix an on /off switch as my slider had stopped working completely from memory //www.mazdatrix.com  sell the dash control box on an exchange basis.

Hope this helps.

All the best Clive
clive@mazdarotaryclub.com
//www.mazdarotaryclub.com

[alistair bridge]

i have an fc that i am breaking. it has afully working heater control panel and blower et cetera. if you are in uk and want a cheap solution pm me and i\'ll sort you out.

Cheers

alistair

[bclaremont]

Unfortunately, I\'m not in the UK, I\'m in the USA.  I\'ve got a bead on a replacement logicon, but I\'m wondering if that\'s the problem.

Clive: I get current through the circuits when the motor is disconnected and I activate the slider control.  Current starts at about 9 volts and builds up to about 13 as the is moved to the right.  Both the low and high speed relays click as well.

With the motor plugged into the circuit only the high speed relay clicks.  I only register current flow through the motor if I place the slider in the max position and turn the ignition on and off.

Did your car exhibit this behavior?

[Jonrms]

sounds like you need a electrician... before you run out and buy anything i think it would be good to call a decent auto electricican.. i have used one several times now as the mazda wiring in my car is a nightmere. i dont know if it is all mazdas fault or if it was the previous owner.. but honestly.. get a electrician.. i know my guy is not only a electrician but a mechanic that done his training on a rx7... funny ha?
anyway he charges 20£ -30£ and thats it.. not per hour.. just by a job.. anyway he has alway been able to fix all my problems..
see if you have a guy local.. or if not.. come to cott.. he will be happy i am sure to look at it..
good luck
if all else fails.. Go for a quick fix in the mean time...
at least you can still drive it..

[alistair bridge]

I guess by your use of the term curent instead of voltage that you are no electronics whizz. no big deal not many people are.. just because your relays are clicking doesn\'t mean they are workoing. turn the switches so that each relay is clicked on then check the resistance accross the secondary terminals. If i had any money i would bet it on the relays being dead (spark erosion , carbon build up etc.

if you can source these you may be able to replace them and your problems will vanish.

look under the wanted section for 2nd gen wiper switch. i bet the same relays are used fir both.

cheers alistair

[bclaremont]

Alistair:  The low speed relay has a resisitor in it that looks like it can be popped out.  When I test across the resistor with the relay unplugged using the ohms setting on my multimeter, I get full voltage.  Is this the correct way to test the resistor?