Another electrical issue please help

Discussion in '2005+ Mustang GT 4.6L Tech' started by swflastang05, Feb 4, 2017.

  1. Wild White Pony

    Wild White Pony forum member

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    I updated the prints in my last post to be a little bigger with notes. If we flashed the pcm to a manual we will need to take the 33 and 32 wires and complete that circuit since when you look at the difference in the auto vs manual schematics thats a closed circuit. We're using that right now as the inhibit since that's what an auto would use. On the manual schematic use the clutch position switch now for the start inhibit, wires 92 Lt-Bl and black to ground. This would be the way FB was using the inhibit. Hopefully that will give us the voltage reference the pcm is looking for and clear the low voltage P0689 code. I'm going to rewire this way, will try and get it done by weekend
     
    Last edited: Aug 9, 2017
  2. 05stroker

    05stroker Never enough power guy!

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    Yall are on to something here. I cant put my mind on it right now since I am out of town working in hell. Im sure I can figure this out after I look at my notes Sunday. I have the same setup from Manuel and have none of the issues yall have. You do have to connect the two wires above from the range sensor . And then is a pin on the auto pcm that needs grounded as well.
     
    Last edited: Aug 10, 2017
  3. swflastang05

    swflastang05 Back for More

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    I see what you're saying, that makes perfect sense, although I think what Billy's saying about grounding one of the pins in the auto pcm harness must be done too since when I plugged in the clutch pedal harness from my wife's manual car into mine it essentially did the same thing (as long as the shifter is in park or neutral) as you're describing but the 689 code remained. I bet the combination of all the wiring revisions will take care of it. My only question would be regarding wire #92 LB-YE in the pcm harness c175b, does the #33 at the connector mean it's pin #33 in c175b? I only ask that since according to the schematic I have of c175b pin #33 is not used, although I don't know if the schematic is for an auto or manual pcm. Either way I have a good feeling about this!

    [​IMG]
     
  4. Wild White Pony

    Wild White Pony forum member

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    That pin out you have is probably for an automatic, once we flashed the pcm to a manual that circuit now exists as seen on the manual schematic above, that pin 33 should now be live.
     
  5. swflastang05

    swflastang05 Back for More

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    Cool, any idea where to get the pin and wire to install into the c175b harness plug?
     
  6. Wild White Pony

    Wild White Pony forum member

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    From your previous post you said.

    "I found the harness in my car up high under the dash on the DS, it just has a loop in the plug on the end where it connects those three devices in manual cars, must just bypass that circuit for auto strategy".

    Why wouldn't you be able to splice into that harness tucked up in the dash, shouldn't those wires run right to the pcm? Your a bit ahead of me on pulling wires from under the dash so I'm not sure till I can get to my car, was planning on tearing into it tonight after work.
     
  7. swflastang05

    swflastang05 Back for More

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    I was referring to the pin in the c175b plug that needs to be grounded, in our auto pcm it's believed to be an empty socket currently.
     
    Last edited: Aug 11, 2017
  8. Wild White Pony

    Wild White Pony forum member

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    I'm not able to read your pin out diagram it's too blurry, can you upload a cleaner pic. In the meantime the pcm has a number of grounds already on that plug, which pin # is the one missing the ground? Here is some of the grounds that should be already in that C175b will have to make a process of elimination.

    [​IMG]

    [​IMG]
     
  9. swflastang05

    swflastang05 Back for More

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    My copy is pretty blurry too, I'll see what I can do to clean it up and re-post. I'm not sure which pin it's supposed to be, Billy was going to check his notes for us on Sunday and let us know.
     
  10. swflastang05

    swflastang05 Back for More

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    See if this is any better?


    [​IMG]

    Yes there are a lot of grounds in that harness already, 5 I believe. The bottom row of 4 wires as well as pin #10. Maybe there's supposed to be 6 in a manual pcm.
     
    Last edited: Aug 11, 2017
  11. swflastang05

    swflastang05 Back for More

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    I took a pic of c175b from my wife's manual pcm, I haven't had a chance to compare it to mine yet but this might help to determine where the extra ground wire is supposed to go.

    [​IMG]
     
  12. swflastang05

    swflastang05 Back for More

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    I fiddled with mine for a bit tonight, I compared my c175b auto harness to my wifes c175b manual harness and found they're identical. I also looked into rewiring my neutral safety circuit per the above and found #32 and #33 wires E10 and B9 in c1035b connector, however I had no luck locating #92 LB-YE. I looked up connectors c215 and c257 are located at the clutch pedal support. On my wifes car those are the clutch position switch (2 red with LB wires, the same that are looped on our auto harnesses) and the cruise control off switch that has a black and white with yellow wire. That entire harness has no LB-YE wires so I'm stumped again. Did you have any luck yet?
     
  13. Wild White Pony

    Wild White Pony forum member

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    I've found wire colors don't mean much with these prints, If you can pull back the covering at C175B and see what color wire is on pin 33. I've attached another schem still showing this wire 92 LTBlu/Yellow on C257. If it's a different color at C257 it may match up to pin 33. The Red/LT-Blu show up on this print for the clutch switch, shown going to the ground. We can always trace 33 to the harness under the dash what ever color it ends up.

    [​IMG]

    I'll check the auto schematics and see if they use wire 92 for something else too, but I would think that that wire has to be under the dash and or miss colored. On another note check your wifes wiring harness connector, see if that LT-Blue/Yellow is on the loop side of that connection. Maybe the color changed after the connection to the manual harness with the switches.
     
    Last edited: Aug 11, 2017
  14. Wild White Pony

    Wild White Pony forum member

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    Went under the dash to look for that PCM side connector for the clutch harness, I couldn't find the LT-Bl/Yellow either so will have to trace. The connector did have a jumper plug to connect the LB/Red together, in the prints they go to black ground. We may have to pull that jumper plug and figure out which RED/Blue is for the clutch position switch ground vs the clutch deactivation switch ground.

    [​IMG]

    Update: Pin 33 at the cpu is Yellow with a green stripe. Back to checking the connector under the dash for that wire.

    [​IMG]
     
    Last edited: Aug 12, 2017
  15. swflastang05

    swflastang05 Back for More

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    Yes the wiring colors are definitely off on mine, and there is no LB-YE on my wifes manual harness, hers has all the same colors are mine, both have the RD-LB colors for that loop.
     
  16. swflastang05

    swflastang05 Back for More

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    Pin #33 on c175b is yellow-green on mine too,
     
  17. Wild White Pony

    Wild White Pony forum member

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    Since you have your wifes pedal harness that connects to C215 connector it should be easy to trace back from the clutch pedal switch to the connector and see which wire it connects to on the other side going to the pcm. That pedal harness from the prints I see has a ground that goes to G204 which would be in the footwell of the left pillar under the cover. We can use that ground to the switch on the shifter and once we determine which wire is the C pedal wire coming from the pcm, it should work as our inhibitor circuit.

    I'm not giving much belief to that C175b connector diagram, it doesn't match up very well with the schematic circuits for that connector. All else fails I'm cutting the wire at the pcm Yellow/Green pin 33 and if it doesn't start then I'm sending that to the ground, if it starts we should be good.

    Track down that jumper on C215, I think one is the brake pedal position going to pin 9 but not sure what the other is or if we need to keep it, I'm hoping the other may be the wire we are looking for.

    Will trace out the circuits from C215 to pcm today and give you a call.
     
  18. swflastang05

    swflastang05 Back for More

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    the two wires are the same red with blue color from the main pcm harness all the way to the clutch pedal position switch. I wasn't able to confirm that either side is ground, the circuit simply closes when the clutch pedal is pressed and the switch is closed. The brake pedal wires are completely separate from the clutch pedal harness.
     
  19. lito

    lito forum member

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    Those wiring diagrams are FOR 07 CARS so they won't match 05-06, they are quite some differences in the wiring and the PCMs are actually not pin compatible with newer year.

    I don't know why Louie mis-labeled them.
     
  20. swflastang05

    swflastang05 Back for More

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    ^^Now that explains a LOT!!!

    Billy are you back yet? We're at a dead end, need your help..
     

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