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I tried the relay to the best of my knowledge. The diagram to cut and splice the wires show that you are supposed to pull a wire from the first connection which is the socket going into the ECU with 22 slots. The other long socket has 26 slots for wires. On the 22 slot i didnt have a 1b for the power connection so I was confused. I also didnt see a violet wire, i only saw like a yellow wire and tried that one.
When i wired the relay i just used the power from my turbo timer since it is in my glove box and it simple to pull power from. I ground the negative to the chassi right below the ECU on a ground contact.
I got the same results as before. I am not sure if this is an ECU issue. The guy I got the car from said that it worked fine when he last used it. Unfortunately the car sat for almost a year before I bought her. What are some sensors or relays I can check to make sure they are not blown or bad?
Old thread, but just wanted to add that I too had A/C issues following the install of the PFC. Watching the commander, the AC status was ok and solid in fan speed 1, but in 2,3 and 4 the status was erratic, blinking on and off, causing the idle to be all over the place.
Like the post above, I really didn't want to hack up the stock harness (and like the idea that I can just plug back in the stock ECU if I need to), so just modified the PFC to include the relay. I got a relay from radio shack (a mini 12v,1a) and wired it in. I lifted the 1E pin and switch the relay off of that pin, then run the switched ground output of the relay into the old 1E through on the PCB. I think in reality, this was easier than crawling around under the dash and trying to splice in new wires/relays.
Anyway, I'm happy to report that the A/C works solidly on all fan speeds now! Thanks to everyone for the relay info!
Hey guys im doing a full write up with pics... i need some help. im doing the internal relay version and these are the scmetatics...http://support.radioshack.com/suppor...oc16/16443.pdf
its radioshack part number 275-0241
Everything is fixed!!! All I had to do was follow the directions.... 10 min idle (without any loads) 10 min with defroster on and 10 minutes with a/c on and defroster off. It literarily took 7 to 8 minutes before the surge stopped! Let it idled for 5 minutes more then turned the car off waited 1 minute and started it again and the surge was gone"!!! So if your idle is bouncing or hunting or surging with the air conditioning on but works on all other settings all you have to do is wait... It sounds easy but all of us who had or have this problem do not like to hear the engine for crazy for longer than 1 minute or two but I was fed up and waiting a few minutes longer fixed it""""""!!,!!,!
My a/c sensor lights up and down every 10 seconds is this normal? I literarily hear the relay click on then after 10 seconds turns off and then 10 seconds later it turns back on. Every time it turns on the interior gauge lights dim down and back up almost as if its taking as urge off power
Hate to resurrect such and old thread, but seems to be the newest I could find.
Went to do this mod last night & it doesn't quite work as expected. It works backwards. The relay switches and A/C comes on in all fan speed positions when the A/C button is NOT illuminated. When the A/C button is illuminated, the compressor doesn't come on.
I thought maybe I got my 87 & 87a mixed up (NO / NC). But when swapped, it works as you would expect, only problem is that when the fan speed is turned off, the PFC sees that the A/C is on.
Any electrical geniuses care to chime in? I hooked it up as follows:
87 - PFC side of 1E (Gray wire / red stripe - 1994)
86 - Harness side of 1E (Gray wire / red stripe - 1994)
85 - 12v ignition, I used the fused side of the blower relay (Blue wire / green stripe)
30 - Chassis ground, 10mm below the ECU
Hate to resurrect such and old thread, but seems to be the newest I could find.
Went to do this mod last night & it doesn't quite work as expected. It works backwards. The relay switches and A/C comes on in all fan speed positions when the A/C button is NOT illuminated. When the A/C button is illuminated, the compressor doesn't come on.
Fixed it with a different 12v source. For some reason the blower 12v is all tied into the speed ****, resistors, and a/c circuit. Oh well. All is good now.
I did the A/C fix over the weekend. The A/C didn't work on ANY of the fan speeds before, now everything works perfectly! Instead of cutting up the harness or running wires all over the place, I just soldered a relay plug to Power FC main board. All the necessary connections are there. If you can find a smaller relay, everything can fit inside the case, but I didn't have one so it is just hooked up from the outside.
The blue wire should go to 1E I assume? But it seems it connected with 1F?
I did the internal solid state relay mod on my Adaptronic Modular and it also seems to have solved the ac fan speed issue. I thought about replacing the harness behind the fan switch, but this relay fix seemed like a more guaranteed fix given that with the harness replacement you're just hoping that replacing that one harness/connector brings the ground down enough to trigger the a/c input properly. The relay ensures that you're always feeding a solid ground trigger.
Did the external relay mod. took the selector switch apart and cleaned the contacts....they were pretty dirty! ....A/C worked on all 4 settings....for about ten minutes then shut off....I've got the FC Commander ECU.....When I touch a test light to the 1E harness side on the relay...the A/C kicks back on and seems to stay on.....I'm stumped.....any ideas?
Last edited by Greg Sabol; Oct 6, 2018 at 10:00 PM.
Did the external relay mod. took the selector switch apart and cleaned the contacts....they were pretty dirty! ....A/C worked on all 4 settings....for about ten minutes then shut off....I've got the FC Commander ECU.....When I touch a test light to the 1E harness side on the relay...the A/C kicks back on and seems to stay on.....I'm stumped.....any ideas?
I know this is an old thread, but there has to be lots of FD owners that have the FC commander ECU and have been through this pain trying to get the A/C to work.
The A/C system has been checked, all components work, freon's good.
The relay mod definitely works....the A/C doesn't work at all without it. But...the A/C doesn't stay on...stays on for a few minutes then the external relay clicks and shuts off. A/C will start up again if I ground the 1E harness side (connected to 86 on the relay). If I connect a ground off the 86 pin on the relay with the 1E harness violet wire still connected to the 86 pin, the A/C stays on, but it can't be shut off by the A/C switch or the fan switch.This violet wire goes to the A/C Thermo switch behind the glove box...then on to the A/C switch on the dash. I've ordered another thermo switch (P/N FD01-61-J20) just in case it's the problem. I'm wondering if the 30 amp relay might be an issue....the 85 pin reads 14volts....a 30 amp relay might be too restrictive. The mod above used a 1 amp relay.
Can anyone help? .......Don't those FC commander guys down under use A/C?....it gets pretty hot down there!
