Guide Permanently fix the "no A/C on fan speed 2/3" problem

Is anybody in the Philadelphia area interested in performing this fix on my 2003 Protege for $200??

My wife has had enough of the AC only working intermittently and I'm going to have to move on from my beloved Mazda if I cannot get it fixed. I was able to pull out the radio and start poking around, but I'm really not sure what I'm doing so I didn't get much further than that.

Please let me know if interested!!

$200!? Jeez. I thought this guide would be detailed enough for nearly anybody to do.
If you still have no idea how to do it, why not buy what's needed (listed) and take it to a shop and have them do it for a mere fraction of the price? Just show them this guide.
 
$200!? Jeez. I thought this guide would be detailed enough for nearly anybody to do.
If you still have no idea how to do it, why not buy what's needed (listed) and take it to a shop and have them do it for a mere fraction of the price? Just show them this guide.

Most shops probably wouldn't do this because they wouldn't want the liability for modifying something electrical in the car.

It's pretty straight forward, only takes about 10 minutes to do it. It's worth giving it a try yourself, just take your time and follow the pictures. the only thing you need to do is remove the radio, you can access everything you need from there. I would pull the fan switch connector out while you're there though and make sure it's not melted.
 
20180922_100131.jpg
A quick photo of what it looks like
Still works a year later.
 
Most shops probably wouldn't do this because they wouldn't want the liability for modifying something electrical in the car.

It's pretty straight forward, only takes about 10 minutes to do it. It's worth giving it a try yourself, just take your time and follow the pictures. the only thing you need to do is remove the radio, you can access everything you need from there. I would pull the fan switch connector out while you're there though and make sure it's not melted.

I'm happy to say that I attempted this today and it seems like it worked! Thanks for the encouragement and of course the initial very-clear, very helpful instructions!
 
I am going to give this a try this weekend or next week. I tried the trick where you cut the black housing to expose the male contacts on the fan switch and connected/soldered the wires and it didn't change anything :/ (Still issues with fan speed 2 and 3). Living in Florida this AC issue can be a real buzz kill when driving my car.
 
I'm happy to say that I attempted this today and it seems like it worked! Thanks for the encouragement and of course the initial very-clear, very helpful instructions!

Kdsmith7, I am happy to see a recent post where this worked. I am going to try it now myself. :D
 
Fixed it. I spliced into the wrong blue/yellow wire. But to be honest the directions should've been more clear. To clear things up for people that'll do this in the future, there are 2 blue/yellow wires in the vicinity. The 1 that you immediately see after removing the stereo is coming from the white plug(fan switch). This is not the right one. You have to splice into the blue/yellow wire coming from the black plug that is under the white plug. lol


Thank you for pointing this out. Made the same mistake as you and was going to live without fan speed 1!!!

The most difficult part was getting the old radio out, had to get my head down by the floormats to see where my homemade removal tool was going. Decided to upgrade to a bluetooth receiver once i got it out.

I would also suggest not "splicing" into the ground wire as mine became messy... just find ground elsewhere...
 
i don't know if this is an obvious question, but wouldn't it be easier to just buy a new fan switch? or just clean the old one as pcb mentioned? my AC has stopped working on 3 and i can still get it to work on 2 if I "wiggle" the switch a bit. 1 and 4 work fine. I'm not too keen on doing modifications to electrical wiring, don't want to create a short or a bigger problem lol
 
Apparently, late model P5's had a redesigned fan switch.
It was a little beefier and could handle more heat and current.
I assume a replacement fan switch would be the newer design.
 
Gonna have to try this. Mine cuts out at speed 4. In Tucson it gets in the 100's, fan speed 3 just doesn't quite cut it unless I turn off the passenger vent which I do most of the time since it's my to/from work car.
 
I have this issue but its intermittent. Not sure if the following irritating workaround works for anyone else but, usually what I do is, turn the AC off for a few seconds before turning the fan speed knob. Then, turn it back on once you have selected your desired fan speed.

A bit of a pain and probably not great to be turning these old units on and off so much, but this workaround seems to have helped the issue progress a little more slowly.
 
Can you guys look at what I did and let me know if I did the wiring/soldering/connecting properly? I am a little nervous about completing this but I am desperate to fix this because everything else I've done such as soldering wires to the fan switch, changing out the blower motor resitor and replacing the fan switch didnt work.

I bought the following for this:
1. https://www.amazon.com/dp/ (commissions earned)
2. https://www.amazon.com/dp/ (commissions earned)
3. https://www.amazon.com/dp/ (commissions earned)
4. Used red butt connectors I had laying around.

The blue wire represents the blue/white wire OP had in his original post.

Here are the photos of what I did before I wrap the resistors area in electrical tape.

https://1drv.ms/u/s!AnjBR5puN_s-hL8bjNuipg-M12lCKg?e=buhUjf
 
Just finished this and the AC works on all fan speeds! Theres no flicker when you switch between any of them either! Ill comment back on this to update whether or not this holds up! :)
 
Hello! CH, are you still around? need some advice.

I tried this fix on my 2002 Mazda Protégé 5 . I used ground to nearby metal frame under dash.
get a solid AC light fan speed 2-5. fabulous!.

BUT..............fan speed 1 is out. like no fan or AC clutch. weird. any reason you can think of?

thanks!
Brian
 
You could have a bad connection inside the switch itself.

Mine was kinda burnt inside.
I took it apart cleaned it a greased it.





 
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Not to resuscitate a necro thread but I just did this "fix" this last weekend on my GFs P5.
Instead of hacking the wiring I did the mod on the PC board itself.

From the connector the sense signal goes to the cathode of diode D5 and from there to the sensing circuit. Instead of the resistor values stated at the beginning of this thread I increased the resistance to 2 K and 1 K Ohms to reduce current draw. As long as the voltage at the junction of the resistors is between 4 and 6 volts it will work fine. I used 1/4W resistors.

I carefully lifted D5 from the board and placed the 2K 1/4W resistor in series from the PC board to the cathode of D5 and reinstalled with just the anode connected to the board.

Then soldered one end of the 1K resistor to the ground pin [third from right, top row] and the other end to the junction of the 2K resistor and D5.

Also replaced the switch. The old one had a couple Ohms resistance between poles. -should have ZERO resistance.
 

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