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Weak blower? Power FC AC issues? Replace or clean your blower switch!
Symptoms:
-Slow Heater/AC blower speed even with blower switch on speed 4.
-Power FC will not engage AC on all or some fan speeds (AC on/off state can be viewed in PFC commander, etc, switch menu)
Root cause:
-Slow blower: Bad contacts in the blower switch act as an additional resistor in the circuit, slowing the blower motor
-Power FC no or flaky AC: The Power FC relies on a ground through the blower switch as an input to determine whether to turn the AC compressor clutch on. Bad ground through the switch = PFC doesn't see the signal.
Solutions:
-New blower switch. I opted for a new switch at about $70.
-Clean and burnish your old switch contacts and plate. I tried a brass wire brush on mine. The switch resistance on speed 3 and 4 went from 10-20 Ohms down to 0. Note: cleaning the switch alone did not help. I had to hit it with the brass wire brush to get the resistance down.
This job was super easy. I was able to get the switch out without taking the dash apart. Only had to pop out my gauges to get to the connector. Access the nut holding the switch in by pulling off the switch handle. A driver won't fit thru the hole, but I was able to use needle nose pliers to R&R the nut with ease.
Careful taking apart the old switch. There is a spring and ball that fits in housing detents for each speed. If you pull it apart too fast it will go flying away. I just took my wire brush to all the contact points until they looked clean.
Air speed coming out of the vents is noticeably faster with the new switch and now I have a solid PFC AC signal on speed 3, which was flaking out before.
THANK YOU! I am needing to do this on my car and didn't realize you could do it without removing the whole HVAC panel.
Dale
NP Dale and Copeland. I didn't realize it was this easy either. I had the switch all winter, but waited for the summer heat to make the plastics less likely to break. I was very happy to find this work-around!
I had the same issue with the Power FC flaking out on speed 3, a new switch resolved it for a little while then it came back intermittently. I swapped out my original PFC with a newer used one (with OLED display, not relevant to this) and that seemed to fix it fully. Didn't think about potential fan speed improvement but it makes sense.
Have fully resolved the issue for good now by returning to the OEM ECU
Yep, the **** just pulls off. It stays on there with friction.
Then you can get regular old needle nose pliers on the nut flats. It's a little tricky to get the nut back on. Just start with the nut at the tip of the jaws and you'll get it back on.
Yep, the **** just pulls off. It stays on there with friction.
Then you can get regular old needle nose pliers on the nut flats. It's a little tricky to get the nut back on. Just start with the nut at the tip of the jaws and you'll get it back on.
Excellent! I'll do that this weekend. Suffered 7's Day heat but definitely not too late to try this before the relay mod!
So I went ahead and pulled my switch yesterday to clean and monkey around with it.
I have a wind speed gauge - basically a fan with a digital gauge that shows wind speed. I had the car running at idle and at speed 4 with recirc on I was seeing 10.5mph airflow out of the left side center AC vent.
Removed the radio and pulled the **** off the switch. The nut is a 14mm, you may be able to find a thin wall socket that could fit but none of mine fit into the hole. I used a small flat head screwdriver to start the nut moving then just continued to spin it off.
The switch is held on with the nut and there's a washer underneath it as well.
The electrical connector was tucked up behind the AC controls, wasn't hard to pull out and unplug. The wiring to the switch is zip tied to a small plastic tab on the back of the AC control box, the little tab broke off as soon as I started removing the switch. I don't think this is really necessary, I think it's there just to keep things tidy for faster assembly at the factory.
With the switch out, it was not hard to pop open to clean. 3 tabs hold it together, just work each one open with a thin flathead screwdriver. There is a ball bearing that's spring loaded on the side of the switch, once it all comes apart that ball will want to go somewhere. In other words, do the job on a clean workbench or table, if you do it standing up in the middle of your yard that's the last you'll see of the ball bearing. Fortunately I was on my workbench .
The ball bearing is spring loaded and pushes against detents in the plastic body of the switch to give the 4 fan positions - it pops into place to give the "click" when you turn the ****.
I cleaned the contacts with a Scotch-Brite pad VERY carefully, just want to clean it down, not sand it down. I then sprayed the contact surface with electronic contact cleaner and wiped clean with a paper towel. When done the contacts were nice and shiny.
I greased up the workings of the switch with some Shin-Etsu grease and put a little dielectric grease on the contacts to help fend off arcing and corrosion in the future.
I plugged in the switch without installing it to test. Unfortunately no change for me - about the same air speed (10.5 or so) from the vent and speed 3 won't kick on the AC (the PowerFC AC bug). So, while the switch was definitely dirty and is original to the car (136,000 miles) it didn't seem to make a change.
I may still buy a new switch just to try that. Next step really will probably be changing out the blower motor for the RX-8 motor, I think a lot of the air speed problems is due to the motor being tired.
In the picture, note the ball bearing to the side. Pro tip for putting it back together, when you start sliding the sections of the switch together there's a notch in the side that you can put the ball bearing in. Start putting the switch together, then put the ball bearing in place and continue to push it together until it snaps.
Putting the switch back in the AC console is like a game of Operation, it's tricky. I had a scribe tool with a wide flat end with a bit of a sharp tip on it, that worked well. It's hard to get the nut in the right place then get it started threading down. Once it's started it's downhill from there. Get it as tight as you can. With the switch in the speed 4 position the flat part of the switch shaft will be at 12 o'clock when you install it.
So I attempted this today, took about half hour max. The only time consuming portion was driving back to my home to get a needle-nose plier since the car is at my folks. Radio needs to be pulled in order to remove the fan switch from the back. The hardest part was pulling out the spade terminals, which I attempted but gave up, they were on really tight! Of course the "I should have looked at this thread again" only to find out I could have unplugged the harness... So I sanded down both ends of the contacts, there was just a bit of black stuff on them. Thanks to Dale Clark on the little ball tip and keeping the switch at the 12'o clock position for fan 4! I was able to put everything back together after cleaning them. The only thing was...I didn't get a chance to test the AC, will attempt to start the car tomorrow. Here are some additional pictures to add to the thread for reference.
Thanks for giving it a try with the wind speed meter... cool toy! That's unfortunate that you didn't see an improvement.
I wonder if starting out you had as high a resistance in your switch as I did or maybe the scotch didn't bite into the corrosion enough. I had to put together/pull apart and use the brass wire brush several times before the multimeter read 0.00 ohms on speeds 3/4. The contacts were pretty jacked up on mine, but I wanted to see if it was possible to reduce the resistance and restore an old switch.
Ultimately I used a new switch. It's possible that the contacts in an old switch just have too much deep contamination to be cleaned easily. I never compared my new switch to the old cleaned switch as far as vent speed or PFC AC switching.
Also, should have mentioned that last year I installed a Four Seasons made in Canada blower motor (on closeout and available for $30 on rock auto). That was a PITA because you have to swap the old blower wheel onto it and it's not easy to get it off the old motor. But... the new motor housing/magnets are much larger in diameter and DC motor diameter has a huge effect on torque.
I wasn't impressed with the new blower right off, but with the new switch it blows my hair around - I don't remember that ever happening before. Wish I had some way to measure it for comparison. Maybe we can meet up at the next DGRR and do a vent speed competition.
The hardest part was pulling out the spade terminals, which I attempted but gave up, they were on really tight! Of course the "I should have looked at this thread again" only to find out I could have unplugged the harness... So I sanded down both ends of the contacts, there was just a bit of black stuff on them.
I would have been really impressed if you managed to pull the spades off the back - they are soldered on there by Stanley Electric Co in Japan.
As I was messing with it I thought I should really put a meter on this . I may have to pull it back out, I still have the radio out at least so it won't be too bad.
The contacts were all bright and shiny when I was done with it. After spraying with contact cleaner I wiped with a paper towel and got some black oxidation off. Another spray and wipe and it was clean.
I'd like to check resistance just for the science of it, see if speed 3 is higher than the other speeds or something.
Started the car today, I can hear the compressor kick in at 1,2 and 4. Fan 3 still doesn't work. I should have used a multi-meter to measure resistance as I was cleaning the contacts. At first I thought my AC wasn't working at all, now I know I have another issue to chase down (AC not being cold even though I charged freon last month along with replacing the compressor with a reman). I'm gonna leave this thread alone and see what results other members have come up with. The summer heat got me defeated.
07-09-19, 08:57 AM
