World's Best | Guitar Wiring Harness | Solder-less Install Each pre-wired guitar harness is built using the worlds best components and craftsmanship, for quality that is guaranteed. SOLDER-LESS INSTALL . No soldering, No soldering tools and No soldering Wire Your Strat · All Pro-Wired Electronics · Wire Your Tele · Les Paul · Custom 4-Way for Tele Why you should not use solder on wiring harnesses May 09, 2012Convormal coating, or heat shrink was used to protect the solder joint. NASA also followed suit, after wiring problems in the Apollo program they got pretty serious about it. Immpoper solder joint allow for "wicking" where the solder runs up the wire under the insulation. It is caused by using too much heat or having the heat applied for too long.