I need to replace the wiring harness for the transmission on my s3 13b. I can only find listings for 12a transmission harnesses and can’t find any info about if they are interchangeable, is it possible to put a 12a harness on a 13b?

 

I believe there is a difference. I think the GSLSE adds a 5th gear switch that’s part of the ECU. You might be able to get a 12a harness and pin in the missing fifth gear lead.

 

So in theory it should work fine other than the 5th gear switch, that’s something I can pretty easily wire in after I get it started.