Before you start
Soldering equipment becomes extremely hot. Work on a heat-resistant surface with ventilation and eye protection, keep the iron in its stand and protect the guitar finish. Disconnect the guitar from the amplifier and any power source. Only undertake work you are comfortable performing; ask a qualified guitar technician if you are unsure.
Photograph the original wiring from several angles and label each wire before removing anything. Identify the pickups and their exact conductor convention. Confirm shaft/bushing length, diameter, knob fit, cavity depth and control spacing. A Les Paul-style model name alone does not confirm compatibility.
Prepare a clean, well-lit workspace and a padded support that does not react with the finish. Keep solder and hot tools away from the instrument surface. This guide covers the supported passive harness; active pickups and additional switching need their own instructions.
Tools
- Temperature-controlled soldering iron and appropriate electronics solder
- Wire cutters, suitable wire strippers and small pliers
- Nut drivers or spanners matching the hardware
- Multimeter and a known-good guitar cable
- Heat-resistant working surface, suitable finish protection and ventilation
Use tools sized for the job. Do not use acid-core plumbing solder. Set up the iron according to the tool, solder and component guidance; excessive heating can damage pots, insulation and the guitar finish.
Step 1 / Identify the circuit
No saved kit has been opened with this guide. Configure your kit or choose the matching circuit before soldering.
Open your selected diagram and check wiring style, capacitor values, treble bleeds and supplied hardware. The diagram includes existing pickups, grounds and any jack or selector you are retaining. “Existing / Not included” means electrically required but not newly supplied.
Open your wiring diagram →Step 2 / Remove the existing controls
Loosen or remove strings only as needed for safe access. Remove cavity covers or other access parts carefully and retain screws. Identify every connection before desoldering it, and preserve sufficient usable lead length. Support a potentiometer or jack while loosening its nut so it cannot twist and pull wires.
Construction differs between guitars. Do not assume a control can pass through an opening or that a connector, mounting hole or cavity is compatible. Stop if removal requires unexpected force.
Step 3 / Install the potentiometers
Test the harness fit before soldering the external connections. Orient the pots so terminals and capacitors have clearance from cavity walls, shielding and covers. Use the appropriate washers and nuts, support each component and tighten only enough to secure it. Avoid twisting the assembled harness.
Do not force shafts or incompatible knobs, overtighten mounting nuts or bend capacitor leads sharply at the body. Check that the control cavity closes without pressing on components.
Step 4 / Connect pickups
Follow the generated pickup-hot and ground connections. Verify your exact manufacturer/model wiring convention before soldering. The Generator’s colour selector identifies which conventions are verified; an unverified choice uses functional generic labels, not guessed colours.
For a standard series humbucker, join and insulate the designated series-link wires as shown. Keep the bare shield on ground. A braided two-conductor pickup does not provide separate access to both coil ends and cannot be treated as a four-conductor pickup for splitting.
Step 5 / Connect the selector
Identify the neck input, bridge input, output contacts and frame ground on the actual switch using its documentation and a continuity meter. Follow the generated diagram, including the joined output contacts where shown. Similar-looking switches may have different terminal arrangements.
If no new selector was ordered, reconnect the existing one to the required circuit destinations. Keep signal connections insulated from the switch frame and nearby shielding.
Step 6 / Connect the output jack
Connect the output signal to Tip and common ground to Sleeve in the supported passive mono circuit. Use a known-good unplugged cable and continuity checks to identify the corresponding contacts. Some multi-contact jacks use several spring contacts for the same electrical node; follow the selected part’s documentation.
Secure the jack without allowing it to rotate and strain the wires. Check that an inserted plug does not touch a signal lug or trap a wire against shielding.
Step 7 / Grounding
Retain the bridge/string ground and connect it to the common ground network shown. Confirm continuity between jack sleeve, specified pot casings, pickup shields, switch frame and bridge/string ground. Shielding, where fitted, must not touch hot terminals.
Do not remove a bridge ground simply to hide a noise problem, and do not modify amplifier mains wiring. Unexplained noise or an unfamiliar grounding arrangement warrants further diagnosis.
Step 8 / Inspect before testing
Check each connection against the drawing. Look for loose or incompletely wetted solder joints, stray wire strands, bridges between adjacent lugs, melted insulation and unwanted contact with shielding. Check ground wires and every component terminal, including places hidden underneath the harness.
Let joints cool before moving them. A large solder blob does not guarantee a reliable connection. Resolve mechanical strain and exposed conductors before electrical testing.
Step 9 / Electrical test
With the instrument disconnected from the amplifier, check intended ground continuity and selector operation. At full volume, check for an unintended near-zero resistance between jack tip and sleeve. A pickup circuit normally presents a finite DC resistance, while a volume at zero intentionally grounds the output; do not interpret every continuity beep as a fault.
Check the resistance changes as each volume is moved and compare selector readings logically. Capacitors do not pass steady DC, so a meter’s resistance or continuity setting cannot confirm a complete tone-control response. Check component values out of circuit where parallel paths would affect the reading.
Step 10 / Functional test
After the basic checks pass, connect to a known-good amplifier at low volume. Confirm neck, bridge and both selector positions; check both volume and tone controls over their full travel. Check for intermittent connections as you gently operate controls, without pulling the wiring.
Play the guitar to assess any treble bleed as volume is reduced. Check additional switching only against its specific verified instructions. The standard Les Paul circuit mutes both pickups when either volume is at zero in the Both position; that is expected for this wiring.
Only refit covers once everything works, ensuring no wires or components are pinched. Retest after final assembly.
Explore this on the bench
Create a physical connection list, conductor reference and printable bench diagram. Each example opens a supported starting circuit; it does not identify your actual guitar or pickup measurements.
Continue learning: Guitar wiring circuits explained → · Pickup conductors and colour conventions →