When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Thanks for the reply AE.... My FD is a 1993 USA east coast...The AC thermoswitch is in the Mana Design evaporator. The Mazda part # for the thermoswitch is FD01-61-J20. This part is discontinued, but with all the AC units out there it's hard to believe there isn't another Thermoswitch that would fit. My AC is working well with the Thermoswitch jumped. To replace the thermoswitch involves removing the evaporator box and disassembling it, because of the long thermoswitch probe tube....it's a pain!
It really wasnt that bad on my RHD car. I mean as long as your system is empty. Disconnect the lines, theres like 2 bolts that holds the thing in once you get the glovebox down. Pops right out.
so when you jumped the AC relay and the clutch pulled in you had ac again? I did that to mine but it still doesn’t blow cold even with the clutch engaged it was pressure tested and refilled the other week and I can see movement of gas in the peep hole on the dryer???
That stumps me....there's something else going on there. If the clutch kicks in, and you see the gas move,....does the fan switch work?
That stumps me....there's something else going on there. If the clutch kicks in, and you see the gas move,....does the fan switch work?
did some more digging, seems the relay earth is at fault, similar to the solution recommended I have a good relay but it doesn’t switch, I opened it up and manually triggered it and the ac clutch kicks in. But mine is a 99 car so different wiring
as for the ac the peep hole goes clear when switched off so I’m thinking there isn’t enough gas, presuming the system wasn’t working fully when they filled it I’m hoping that ment it couldn’t be filled up fully? Going to jump the relay and get the garage to check the system over again
I believe if I use 4V on the later ECU this is the same input as 1E in the relay fix mentioned above
Last edited by mpk490p; Aug 9, 2020 at 04:12 PM.
Reason: Added wiring diagram
My A/C would only work on speed 1 and sometimes 2. I followed these instructions. R12 feels amazing.
Category Five Motorsports
Power-FC A/C MOD
This mod will enable your air conditioner to work when installing a Power FC in FD3s. This will also fix the problem of the a/c not working on one or more of the fan speeds.
The reason the a/c does not come on is because as the car ages, the ground signal going to the ECU’s (wire 1E) is receiving a fuzzy ground signal. Some cars have no problem with the signal, but some do; the last FD I worked on the a/c did not work on any speed. My mod will interrupt the signal going into the Power FC and redirect it through a simple Bosch relay. This will also let the Power FC still control the IAC and switch the a/c off at wide open throttle.
Locate wire 1E (Violet wire) - it is the third wire from the end on connector one. Cut the wire 2” from ECU. On the harness side you will hook 1E to (86). On terminal (85) on the relay will go to ignition +. Terminal (87) will go to 1E that was cut on the Power FC side. Terminal (30) will go straight to chassis ground. Now when your a/c is turned on, it will receive a nice healthy ground. If you have any questions contact me via email.
I am still having issues as I have a 2001 model and the pin layout is different to the 93-94 spec cars which is the only wiring diagrams I can find.
I did the mod as per the instructions, Using the only violet wire in the harness, but the relay isn't being activated.
I figured out the wire that runs to the relay Yellow/Black stripe, but I am not 100% sure that the violet wire is the right one, as it is on a different connector.
If I can activate the relay then we are all good. I am considering just putting in a manual switch. Really frustrating especially when it is summer here in Australia.
did you get this resolved? Think I’m having the same issue with a 99
Resolved my issue by putting a time delay relay (5secs) that gives earth to I4 (ac relay) the trigger is from V4 I found I could manually push the ac relay and it would hold if the relay was on, the time delay relay now does this and I have all safety and ECU idle control as it should be
Alright, I'm getting ready to do this mod now that summer has ended. I have a 95 USDM FD, and cannot locate the purple wire (writeup was for a 93). I want to confirm that Pin 1E is the Gray/Red wire. I traced the circuit from ground (forgive me for the terrible screenshots), please see below.
So this is connector 1, from the bottom of the Power FC. Third from the end is Pin 1E, the Gray/Red wire. I just want a confirmation before I cut the wire. Thanks in advance!
Update: The Gray/red wire is indeed Pin 1E for a 94-95. It was too hard to work underneath the dash so I bought a Banzai Racing patch harness just for the convenience and not butchering the OEM wiring. Used pin 1A for the 12V. 4A, 4B, and 4C are the same ground so I went with 4A. Used an 8616 5-pin relay on Amazon, left the 87a wire disconnected. I used butt connectors instead of solder for now, until I decide to add another wire if I want to install a fan for the AC. Everything works now.
Thank you for this writeup. Earlier this summer when I was restoring AC in my 94, I stopped just before cutting the wire as it was a different color than mentioned in the old forum comment. Good idea getting the patch harness, I'm gonna go that route.
Really hate that I can't figure this out myself and have to revive a dead thread, but I guess that's what forums are for.
So, I did this mod. My AC worked on all 4 settings, but there's a draw somewhere. Engine fans stay on after turning the car off. Battery dies if sitting for a few hours. Half the time when starting, the rear wiper and defroster is on (even if I unplug the switch). I've since reverted the wiring and its back to normal (AC only works on 1 and 2). Any ideas?
I didn't use an inline fuse with the relay btw.
EDIT: And now I see there's a newer thread about this right at the top of the page.... great🤦♂️
I skipped all the reading and just copied Billy 7 pictures a few posts up. A/c works flawlessly now. It was much easier to see how to do it than read how to do it. My $.02
I did the relay mod it worked for awhile.......then the thermoswitch had to be jumped to get it to work......It's April 2024 now......The A/C isn't working again....All the fan speeds work, the A/C clutch doesn't come on anymore, A/C relay tested OK, Clutch works when jumped to + , thermoswitch jumped....can't get the clutch to engage....I removed the relay mod and just did a direct connection.....1E to 1L on the harness side, this bypass's the PFC ECU. Still no A/C....I'm stumped again! This A/C problem is such a pain, no A/C in Florida summers makes driving the FD no fun!
I did the relay mod it worked for awhile.......then the thermoswitch had to be jumped to get it to work......It's April 2024 now......The A/C isn't working again....All the fan speeds work, the A/C clutch doesn't come on anymore, A/C relay tested OK, Clutch works when jumped to + , thermoswitch jumped....can't get the clutch to engage....I removed the relay mod and just did a direct connection.....1E to 1L on the harness side, this bypass's the PFC ECU. Still no A/C....I'm stumped again! This A/C problem is such a pain, no A/C in Florida summers makes driving the FD no fun!
Do you have enough refrigerant in the system? If the pressure is low, then the compressor clutch will not engage. You can test this by jumping the pressure switch next to the drier.
