sc400 engine wiring harness
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7th Gear
Joined: Sep 2020
Posts: 7
Likes: 1
From: Texas (TX)
sc400 engine wiring harness
hey, I've searched around and can't find anything. I have a 95 sc400 and had to replace the engine wiring harness and I'm not sure what year models have the same connectors and set up. I already bought a 97 wiring harness and the connections are different and I'm not sure what year model I should be looking for.
What has happened that has required you to replace the entire engine wiring harness?
There were some revision changes during the model run. I believe the revision changes for SC400's were: 1992-1994, 1995, 1996-1997, 1998... and I am not sure how it works out for 1999 and 2000. But you will want to stick with an OBD1 harness at minimum if you're looking for one. That means no later than your own SC400 model year of 1995.
........
As these cars are getting very old now in 2020 and it may be difficult to find the exact harness you need in good condition (in reality most used harnesses will need at least minor repairs), here is the best way to restore your own harness:
Remove the engine wiring harness from the car, get it inside and start going through it to test and repair wiring connections with a common electrical multimeter set to continuity with a beep every time you match one pin to its corresponding pin.
It will help to have the 1995 SC400 electrical TSRM PDF handy to look at the wiring pinouts of your engine harness between: the ECU, body/chassis plugs and every connector that goes onto the engine.
For broken connectors and frayed or broken wires, what you do is look at each physically damaged connector and read the five-digit Toyota P/N on it. Then you have to add "90980-" to precede each such number embossed into the connector plastic. Let's say the five-digit number embossed on a broken engine harness connector is "12345".
That means you'd go to a Toyota (or Lexus) dealer and ask to order connector 90980-12345. Add to that, the dealer can look up the correct matching terminal repair wires that go to that specific connector. It's a little more lookup work for them but they can do it. But they cannot help you unless you give them the correct connector part number to begin with.
From there you can go about replacing bad connectors with new ones and soldering in new connector terminal repair wires (using small electronics heat shrink tubing.
To re-tape the engine harness (because you will be unwinding parts of it in order to do this job) you can use Scotch Super 33+ electrical tape or to be a bit more OEM for *final* wrapping, use Tessa #51036 engine harness tape.
As far as longer lengths of wire with which to repair *long* wire paths inside a Toyota engine harness, the best stuff if what you'd pilfer from another original Toyota engine harness such as the SC400 1997 harness you already have. However I'd hold off on tearing into that one to cannibalize unless you are 100% sure you absolutely have to once you've observed damage to your 1995 harness that makes it unavoidable.
Needless to say that any engine harness reconditioning or work can become a time consuming process. ALWAYS refer back to the SC400 electrical TSRM for your model year for reference while working if you happen to take on a harness repair job, go slowly and double check your work as you go. It's not rocket science, just meticulous and the time involved just depends on what needs to be done
That said I hope you can get by with just minor connector and terminal wire end replacement and/or find yourself another 1995 SC400 engine harness.
There were some revision changes during the model run. I believe the revision changes for SC400's were: 1992-1994, 1995, 1996-1997, 1998... and I am not sure how it works out for 1999 and 2000. But you will want to stick with an OBD1 harness at minimum if you're looking for one. That means no later than your own SC400 model year of 1995.
........
As these cars are getting very old now in 2020 and it may be difficult to find the exact harness you need in good condition (in reality most used harnesses will need at least minor repairs), here is the best way to restore your own harness:
Remove the engine wiring harness from the car, get it inside and start going through it to test and repair wiring connections with a common electrical multimeter set to continuity with a beep every time you match one pin to its corresponding pin.
It will help to have the 1995 SC400 electrical TSRM PDF handy to look at the wiring pinouts of your engine harness between: the ECU, body/chassis plugs and every connector that goes onto the engine.
For broken connectors and frayed or broken wires, what you do is look at each physically damaged connector and read the five-digit Toyota P/N on it. Then you have to add "90980-" to precede each such number embossed into the connector plastic. Let's say the five-digit number embossed on a broken engine harness connector is "12345".
That means you'd go to a Toyota (or Lexus) dealer and ask to order connector 90980-12345. Add to that, the dealer can look up the correct matching terminal repair wires that go to that specific connector. It's a little more lookup work for them but they can do it. But they cannot help you unless you give them the correct connector part number to begin with.
From there you can go about replacing bad connectors with new ones and soldering in new connector terminal repair wires (using small electronics heat shrink tubing.
To re-tape the engine harness (because you will be unwinding parts of it in order to do this job) you can use Scotch Super 33+ electrical tape or to be a bit more OEM for *final* wrapping, use Tessa #51036 engine harness tape.
As far as longer lengths of wire with which to repair *long* wire paths inside a Toyota engine harness, the best stuff if what you'd pilfer from another original Toyota engine harness such as the SC400 1997 harness you already have. However I'd hold off on tearing into that one to cannibalize unless you are 100% sure you absolutely have to once you've observed damage to your 1995 harness that makes it unavoidable.
Needless to say that any engine harness reconditioning or work can become a time consuming process. ALWAYS refer back to the SC400 electrical TSRM for your model year for reference while working if you happen to take on a harness repair job, go slowly and double check your work as you go. It's not rocket science, just meticulous and the time involved just depends on what needs to be done
That said I hope you can get by with just minor connector and terminal wire end replacement and/or find yourself another 1995 SC400 engine harness.
Thread Starter
7th Gear
Joined: Sep 2020
Posts: 7
Likes: 1
From: Texas (TX)
What has happened that has required you to replace the entire engine wiring harness?
There were some revision changes during the model run. I believe the revision changes for SC400's were: 1992-1994, 1995, 1996-1997, 1998... and I am not sure how it works out for 1999 and 2000. But you will want to stick with an OBD1 harness at minimum if you're looking for one. That means no later than your own SC400 model year of 1995.
........
As these cars are getting very old now in 2020 and it may be difficult to find the exact harness you need in good condition (in reality most used harnesses will need at least minor repairs), here is the best way to restore your own harness:
Remove the engine wiring harness from the car, get it inside and start going through it to test and repair wiring connections with a common electrical multimeter set to continuity with a beep every time you match one pin to its corresponding pin.
It will help to have the 1995 SC400 electrical TSRM PDF handy to look at the wiring pinouts of your engine harness between: the ECU, body/chassis plugs and every connector that goes onto the engine.
For broken connectors and frayed or broken wires, what you do is look at each physically damaged connector and read the five-digit Toyota P/N on it. Then you have to add "90980-" to precede each such number embossed into the connector plastic. Let's say the five-digit number embossed on a broken engine harness connector is "12345".
That means you'd go to a Toyota (or Lexus) dealer and ask to order connector 90980-12345. Add to that, the dealer can look up the correct matching terminal repair wires that go to that specific connector. It's a little more lookup work for them but they can do it. But they cannot help you unless you give them the correct connector part number to begin with.
From there you can go about replacing bad connectors with new ones and soldering in new connector terminal repair wires (using small electronics heat shrink tubing.
To re-tape the engine harness (because you will be unwinding parts of it in order to do this job) you can use Scotch Super 33+ electrical tape or to be a bit more OEM for *final* wrapping, use Tessa #51036 engine harness tape.
As far as longer lengths of wire with which to repair *long* wire paths inside a Toyota engine harness, the best stuff if what you'd pilfer from another original Toyota engine harness such as the SC400 1997 harness you already have. However I'd hold off on tearing into that one to cannibalize unless you are 100% sure you absolutely have to once you've observed damage to your 1995 harness that makes it unavoidable.
Needless to say that any engine harness reconditioning or work can become a time consuming process. ALWAYS refer back to the SC400 electrical TSRM for your model year for reference while working if you happen to take on a harness repair job, go slowly and double check your work as you go. It's not rocket science, just meticulous and the time involved just depends on what needs to be done
That said I hope you can get by with just minor connector and terminal wire end replacement and/or find yourself another 1995 SC400 engine harness.
There were some revision changes during the model run. I believe the revision changes for SC400's were: 1992-1994, 1995, 1996-1997, 1998... and I am not sure how it works out for 1999 and 2000. But you will want to stick with an OBD1 harness at minimum if you're looking for one. That means no later than your own SC400 model year of 1995.
........
As these cars are getting very old now in 2020 and it may be difficult to find the exact harness you need in good condition (in reality most used harnesses will need at least minor repairs), here is the best way to restore your own harness:
Remove the engine wiring harness from the car, get it inside and start going through it to test and repair wiring connections with a common electrical multimeter set to continuity with a beep every time you match one pin to its corresponding pin.
It will help to have the 1995 SC400 electrical TSRM PDF handy to look at the wiring pinouts of your engine harness between: the ECU, body/chassis plugs and every connector that goes onto the engine.
For broken connectors and frayed or broken wires, what you do is look at each physically damaged connector and read the five-digit Toyota P/N on it. Then you have to add "90980-" to precede each such number embossed into the connector plastic. Let's say the five-digit number embossed on a broken engine harness connector is "12345".
That means you'd go to a Toyota (or Lexus) dealer and ask to order connector 90980-12345. Add to that, the dealer can look up the correct matching terminal repair wires that go to that specific connector. It's a little more lookup work for them but they can do it. But they cannot help you unless you give them the correct connector part number to begin with.
From there you can go about replacing bad connectors with new ones and soldering in new connector terminal repair wires (using small electronics heat shrink tubing.
To re-tape the engine harness (because you will be unwinding parts of it in order to do this job) you can use Scotch Super 33+ electrical tape or to be a bit more OEM for *final* wrapping, use Tessa #51036 engine harness tape.
As far as longer lengths of wire with which to repair *long* wire paths inside a Toyota engine harness, the best stuff if what you'd pilfer from another original Toyota engine harness such as the SC400 1997 harness you already have. However I'd hold off on tearing into that one to cannibalize unless you are 100% sure you absolutely have to once you've observed damage to your 1995 harness that makes it unavoidable.
Needless to say that any engine harness reconditioning or work can become a time consuming process. ALWAYS refer back to the SC400 electrical TSRM for your model year for reference while working if you happen to take on a harness repair job, go slowly and double check your work as you go. It's not rocket science, just meticulous and the time involved just depends on what needs to be done
That said I hope you can get by with just minor connector and terminal wire end replacement and/or find yourself another 1995 SC400 engine harness.
luckily I’m having it rebuilt so it can be back on the road, all that’s left is the wiring.
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