Sonicjv Posted December 27, 2021 Share Posted December 27, 2021 I have a 89 comanche with 4.0 (manual transmission) and I recently replaced the engine wire harness but I believe it was out of a automatic comache. Everything went great except one connector on the passenger side firewall. My truck has no spot to hook to but I believe this is the wire that goes to what would have been an auto transmission. I think it controls neutral safety switch. Is there a way for me to make this work on my manual trans? Bypass or new connector maybe? Link to comment Share on other sites More sharing options...
boxyjeep Posted December 27, 2021 Share Posted December 27, 2021 There should be a switch somewhere on the manual transmission that indicates when it's in reverse (to turn on reverse lights). I'd trace that back and see if it is connected anywhere (possibly needs to be plugged in here). There should be a connector for the automatic TCU (passenger firewall), as well as the transmission itself (for NSS). If you want to get creative, you can figure out what wire triggers the reverse lights, as well as which one connects to the starter relay (to only allow start in Park or Neutral). Link to comment Share on other sites More sharing options...
Sonicjv Posted December 28, 2021 Author Share Posted December 28, 2021 That's kind of what I was thinking. Would anyone know what wires do what on the TCU Link to comment Share on other sites More sharing options...
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