|I tried to find factory wiring for this guitar but no schemantics on GIBSON official web site. Also no information on web. Here some photos of original wiring . Guitar must be rewired so that neck PU 490R is replaced and installed , while bridge PU 498T is taken out and rewired, and than wiring harness is installed in the body. God news is that wodwork and materials GIBSON
Memphis used are wery good and this guitar deserves better PU &simplified ES-175 wiring. Here is how I rewired and upgraded my
guitar. First tailpiece should be changed to ABM fingerstyle -gold the one used on Howard Roberds Fusion III .
That is because sound is radically different more like ES-335 & ES-175. Howard Robers Fusion III does not use wood block
inside and sound is more like ES-175 but upgrading to fingerstyle tailpiece is much better. Also changed the bridge to
ABM tailpiece and Roller 2400-gold .
This makes ES-137 look and sound close to Howard Roberts Fusion III although it is slightly larger than Fusion model. Here is how I rewired the guitar in photos : The original factory wiring is very complicated due to fact that uses very small tone caps that cost maybe 5 cents each and are attached on tone pots, versus caps connected between volume and tone pots. Original factory volume & tone pots are 500 kOhm. Original neck PU 490R is aprox 8 KOhms and bridge PU 498T is 14 KOhms. I replaced neck PU with DiMarzio PAF Pro 4 conductor PU 7,8 KOhms having the same south magnetic polarity as GIBSON 490R. I wired it using push-pull pot as per schemantic from Smith's photo in order to get coil split and humbucking sounds.Each coil can be a single coil and mixed with hummbuckig sound. Only drawback is that you cannot turn down volume on this neck PU however, you can easily switch to middle position turning down completely volume of bridge PU.
I put Russian PIO Capacitor K40Y-9 Series 200V 0.22~1uf .
This mod gives ES-175 humbucking sound, ES-335 and LP humbucking sound and close to ES-175 single coil sounds and turns this nice guitar into really multiple sounds fusion guitar like Gibson HOWARD ROBERTS FUSION III model.
The neck PU ( DiMarzio PAF PRO ) works like this :
When volume pot is pulled up and rotated completely to the left only 1 coil close to the neck is active and you get single coil-sound like on a Strat guitar.
When rotated to the full right you get full humbucking sound with both coil active.
When volume pot is pushed down same as above applies only in single coil mode 1 coil next to the middle of guitar is active.
If you put PU switch on the upper bout of guitar to middle position you can use bridge PU volume pot as master volume for both PU ( pickup units) .
I replaced tuners with SCHALLER LOCKING TUNERS same as on Howard Roberts Fusion II model.