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A/C issues?

Greetings my P5Peeps!
So, an A/C specialist just told me I need to replace the a/c "control module". He wants 600 plus parts... I am looking at my service manual, and I don't see a specific "module" per say, and two Mazda dealer parts monkeys don't know what I am talking about! Is there such an animal? It is already in the 90's here in SoCal.... I need A/C....
I tried the on/off trick already and it didn't work.... Looking for RELIABLE help on this as I am fairly new to working on the car myself...
Thanks!
 

pcb

The Diagram Dude
:
2002 MP5
Does the fan blow?
Does your AC light come on?
Does it flicker?

Did you remove your console to paint it?
 
Does the fan blow?
Does your AC light come on?
Does it flicker?

Did you remove your console to paint it?
Fan blows
No AC light
No Flicker
I have not yet... (But someone might have bc there is overspray at my cup-holders and shift boot area)
But I DID have a new stereo installed...
Thank you
 

pcb

The Diagram Dude
:
2002 MP5
I say check your fuses and relays.


















I think you should pull your console to see if everything is connected.
(It'll give you a chance to repaint it too.)

A wire or connector may have been pulled off or not reconnected.


The only "control module" I can think of is the circuit board behind the console and I don't recall anyone that has had one fail. (except for the flashing AC light at fan speeds 2&3)


 

pcb

The Diagram Dude
:
2002 MP5
No...

Those are the two copper runs that you cut to do the Defog Mod.

I didn't want my AC running all winter long.

Now it only turns on when I push the AC button.

Just enough to stir the oil.
 
That makes more sense. In NB Miatas we have the same concern; the "fix" is to unplug a connector behind the output selector knob that actuates the compressor on defrost.
I will be looking at Rona's car this weekend and will try a couple of things. Most likely will wind up doing the voltage divider trick, a couple of 15 cents resistors is a lot cheaper than the alternative :)

And by the way, thanks for the info on fuses and relays location!!! (y)
 

pcb

The Diagram Dude
:
2002 MP5
...
I will be looking at Rona's car this weekend and will try a couple of things. Most likely will wind up doing the voltage divider trick, a couple of 15 cents resistors is a lot cheaper than the alternative :)

I'm suspecting that the resistor fix may not work in this case because her AC light doesn't come on at all or even try.

The resistor fix is for a flickering AC light on fan speeds 2&3.

I suppose that the "sense circuit" could cut out the AC at all fan positions but I don't recall that being the case.


Be careful when you pull the "shroud/console". It only moves about an inch or two before you start pulling on the wires and control cables.

Try to mark the position of the clips holding the control cables before you unclip them so you can clip them back in at the same position.


Check the condition of the fan switch connector. It gets all burnt and melted.
It can completely burn up to where you have no fan at all.










AC pinout diagram...




I bypassed my connector and soldered new clips on the wires to provide a better connection with less chance of tripping the sense circuit.





ZapWizard did an awesome how-to that covers the removal of the console but his pictures disappeared years ago...





 
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Thanks for the tips, greatly appreciated.

Mazda has issues with connectors burning like that; first generation Miatas have a habit of melting the ignition key switch connector as well.
The short movement of the control panel is typical.
Whether the light flickers or not, far as I can tell the sense circuit is the go/no go point for compressor clutch engagement.

I have the car's wiring diagram, need to spend a few minutes following the AC circuit.
 

pcb

The Diagram Dude
:
2002 MP5
I'm suspecting that something was disconnected/broken when the console was removed.

I forget if it has to be removed to replace the stereo?
 
I'm suspecting that something was disconnected/broken when the console was removed.

I forget if it has to be removed to replace the stereo?
Yes, it was removed and a new head unit installed. -not by me, though. Thanks for the suggestion.
 

pcb

The Diagram Dude
:
2002 MP5
Take note of the cable routing when you remove them from the console.

I messed that part up and it took me quite a while to get them re-routed properly.
 
Problem resolved. Friday I took a look and noticed that the rear defrost and the lights on the inside/outside bar were not lighting. It had to be a power source issue. Room fuse was ok, still had instrument lights.

The main connector to the HVAC unit was partially disconnected. Snapped it on and now Rona has cold air!!!

Thanks for all the suggestions, greatly appreciated.
 

pcb

The Diagram Dude
:
2002 MP5
Cool !

I don't see how that was $600 worth of effort.
I wonder if the AC specialist would have sold her a new HVAC unit as well ?
 

pcb

The Diagram Dude
:
2002 MP5
Keep an eye out for the flickering AC light.

It happens to almost all if us.

There's the resistor fix but I didn't want 10 amps running though my fan switch so I installed a bunch of relays.
Now I've only got 20 mA running through my switch.
 
Cool !

I don't see how that was $600 worth of effort.
I wonder if the AC specialist would have sold her a new HVAC unit as well ?
I think that he may have noticed that the control panel wasn't working and figured "a new module" would fix it...
 
Keep an eye out for the flickering AC light. ...It happens to almost all if us. ... There's the resistor fix but I didn't want 10 amps running though my fan switch so I installed a bunch of relays.
Now I've only got 20 mA running through my switch.
Will do. You're talking about full motor current through the switch? Yeah, that would certainly shorten its life.
You want less than 20 mils going thru the switch? Use a Solid State Relay, turn on current ~5-7 mA. :)

The motor/squirrel cage will need to be replaced sometime in the near future; the motor is noisy, sounds like a bad spot on the commutator, makes a "click" noise every 1/2 revolution.
 

pcb

The Diagram Dude
:
2002 MP5
But would he have just simply have plugged in the HVAC unit for $600 or would he charge her for a new one as well?


Mechanics an be crooks.

My neighbors sister was charged $50 to replace her blinker fluid.

He went to the shop and said if you don't give her her money back, I'm phoning the cops
 
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