Threading transducer wire from back to console.

Help. I am trying to help neighbor with my old 2001 Pantera III run cable from transducer to console. I have done this many times on many boats but this one stymies us. We have tried vaseline and silicone spray and still cannot get through. We bought 3 different fish tapes and one is no better than the last. We have taken off rear air scoop and loosened the throttle area trying to get it done. I am hoping someone has some piece of magic for us. If there is a wire bundle half-way back how can we get it undone? Is there something different with the PIII? By the way, this PIII is still a terrific ride and the guy has it shining like it came off the showroom floor. Thanks for any suggestion, no matter how simple or difficult or silly.