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AC Compressor not getting power 95 Accord

Home Forums Stay Dirty Lounge Service and Repair Questions Answered Here AC Compressor not getting power 95 Accord

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  • #663129
    Michael ManleyMichael Manley
    Participant

      Hello I have a 1995 Honda Accord EX with 200,525 miles on it. The AC Compressor is not getting power.

      I think i pinpointed the issue but I’m wondering if its fixable or might have to replace the harness. The Car acts as such when the AC is on (RPM’s rise, all fans turn on) The computer is showing command to the AC Clutch (as shown by AC Switch, and AC Clutch being on using a Honda Scantool) but not starting the compressor.

      I directly engaged the clutch and it engaged so it must be an issue to the relay and the relay is showing on the coil side 8V from the wires. Isn’t it spoce to show 12V?

      I am thinking of replacing the harness but from what i seen is its own harness but on my car it looks part of the drivers side engine harness, if it is how hard is it to replace?

      Would this be a right call due to it looks like someone repaired it but not correctly (it had wire nuts before) and maybe the wires got damaged internally and is causing more resistance? Or should i look at other things. I don’t think its the switch due to the compressor fan coming on and the ECU commanding what normally happens to prep for the compressor.

    Viewing 15 replies - 1 through 15 (of 17 total)
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    • #663130
      DanielDaniel
      Participant

        First, kudos on the diag procedure.
        I’m not real familiar with the older Honda systems, but I beleive it should be 12v. Your wiring sounds like it could be bad. Keep in mind, not only will breaks cause current pressure issues, but so will old/coroded/oxidized wiring or contacts. Check the contacts. Try soldering and shrink wrapping those connections. If that doesn’t change anything, you could just replace those wires instead of buying a whole new harness.
        Take a look at the high and low side relays as well. If one of them went bad they could cause an issue like this.
        Good luck.

        #663136
        AllanAllan
        Participant

          Hello 🙂
          You mean that you have 8v on that blk/yel wire (comes from fuse nr8) ?
          And ECU ground circuit when ac on, red/blu wire ?

          #663138
          Michael ManleyMichael Manley
          Participant

            Correct. Fuse 8 isnt blown either.

            #663141
            AllanAllan
            Participant

              Ok 🙂

              Maybe check 12v at Connector 309 pin 4..

              Attachments:
              #663163
              Michael ManleyMichael Manley
              Participant

                Yes gets 12V.

                Odd that the blk/yel wire gets 12V, wht gets 12V, and red/blu gets 6.3V (isnt that a ground to the ECU?) and red reads 0V (obviously) at the relay plug (this is with the AC on)

                #663182
                AllanAllan
                Participant

                  ok.. you have 6.3v on red/blu when you take relay out too?

                  #663184
                  Michael ManleyMichael Manley
                  Participant

                    Yes all this was done without the relay.

                    I don’t remember if the engine was running when i checked the red/blu wire but i was sure if the ECU isn’t commanding the clutch on it would be 12V instead of a ground, wonder if that wire is whats bad.

                    I thought id mention i have done a modification to the dash (installed a 97 CL dash in) and wired everything to the Auto Climate Control system, Though if it was that wouldn’t that be an issue at the switch level and none of the AC Components would work? As the ECU is obviously commanding things on, just no compressor action. And the wiring that was modified was before the AC Thermostat and not after. (The AC Thermo wiring is just bridged with a 3pin Plug and it gets control from the CL’s Climate Control Unit) I could test to see if its that by grounding out the BLU/YEL wire but im 99.9% Positive its not that.

                    #663185
                    AllanAllan
                    Participant

                      Ok 🙂 Wiring diagram for 95 year, show that Control side get 12v from fuse8.. Then other has to be ground.. From ECU yes..
                      Sure Your wire from ecu to relay could be bad .
                      Have you mesure at pin 8 at ecu conector C458?

                      Attachments:
                      #663188
                      Michael ManleyMichael Manley
                      Participant

                        Ok when i get a chance ,later today or tomorrow ill check the ECU as im at work and i cant really quick test that.

                        #663204
                        Michael ManleyMichael Manley
                        Participant

                          Ok Pin 8 on C458 is 6.66V from the ECU

                          #663235
                          Michael ManleyMichael Manley
                          Participant

                            I’m pretty close to condemning the ECU but I want to be 100% certain, even tho 94-95 Accord EX ECU’s are a dime a dosen at the junkyard I just don’t want to be part swapping lol.

                            I’m going to unplug my ac thermostat jump wire then test again to see if it still reads 6, or 12 to see if its that, if its still reads 6 its not my modified wiring cause thats pre ac thermostat. Least I can take my modifications out of the equation.

                            Is there any other tests i can do before calling an ECU?

                            Sucky thing is i have a 95 Accord ECU laying around but its for an LX model and I’m afraid to even check things with it because its for a F22B2 engine and not an F22B1 engine.

                            On a side note, i noticed lately my CEL hasn’t been turning on but idk if thats a ECU fault or just a wiring/bad bulb issue. If i end up replacing it and that ends up working too i guess i had a faulty ECU all along, just GOOD enough to run the car lol.

                            #663265
                            AllanAllan
                            Participant

                              Yes, dont be a part changer :p
                              That pin 8 should have 12v ac comressor off, and ground ac compressor on.. The input to ecu , C459 pin3 red/white wire should have 12v ac off, and ground ac on. You could check that 🙂

                              #663271
                              Michael ManleyMichael Manley
                              Participant

                                Well, i took a plunge and installed my known good LX ECU (I just didn’t start the car with it, I heard it would run anyway until VTEC kicks in and then it would run like garbage) just to check what it returns on the red/blu wire. Of course 12V, so i think its safe to say its the ECU. (Sometimes its lucky to hold onto parts even if you never plan on using them for anything xD)

                                It just seems odd, i never shorted nothing out nor when i did the dash swap did i leave the battery plugged in.

                                #663275
                                AllanAllan
                                Participant

                                  Ok 🙂 But you find the problem.. 🙂

                                  #663696
                                  Michael ManleyMichael Manley
                                  Participant

                                    Just want everyone to know the outcome of this.

                                    So it was the ECU, once i replaced the ECU and the left engine bay harness (it was about the same to replace the whole harness with a junkyard one then to fix the existing one, since it was like 10 wires that were bad on it and it wasn’t hard to access since i was replacing the fender anyway) the compressor engaged and now i finally have AC working perfectly.

                                  Viewing 15 replies - 1 through 15 (of 17 total)
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