A brief walk through of the pick-up replacement process.
Here you can see the original stock Lace Sensor, and the aftermarket Fender branded replacement. (notice the inset logo area on the pick-up top, as well as the three wires on thereplacement. The green wire is ground.)
The back of the same pair of Lace Sensor Blue single coil pick-ups. 
The Blue Lace Sensor is meant to replicate the tone of a vintage hum-bucker. The Silver Lace Sensor a 70s era single coil tone, and the Gold Lace Sensor a vintage single-coil pick-up. Lace Sensors were stock pick-ups on select American made Stratocasters for many years appearing on the Jeff Beck, Eric Clapton, Robert Cray, Buddy Guy, Plus, Plus Deluxe, and Ultra series Stratocasters – and a few Telecaster models as well.
I had previously replaced the wiring in this guitar, following the schematic diagram from the Lace website for Volume pot, Tone pot, and tone cap values. The Lace single-coils work well with 250k pots. My finding is that 500k pots tend to make them sound brittle. Sensors have a very even string response due to their unique design, with a reduced magnetic pull. They also have a wider dynamic range than traditional single-coils. I find them good for recording and driving effects. With the wiring ready to go, I simply cut and stripped off fresh wire to make the new connections.
Here you can see my quick rewiring job that had been done previously. Nothing fancy. Just functional wiring that follows the specified diagram.
I attempted to diagnose the problem with the original Lace Sensor Blue, however my testing with a multi-meter proved inconclusive.
I like to use solid or stranded copper lead wires to make the initial soldered connections to the components – rather than direct connections to the thinner, fragile, pick-up lead wires. Simple short lengths like this with both ends stripped are prepared and installed as needed. This technique can also come in handy when swapping pick-ups around that have shortened lead wires.
Simple solid copper wire jumper, ready to install.
Here you can see the jumper wires installed and ready for the connections to the output wires (positive and ground), and pick-up leads which are also positive and ground – with the new pick-up having an additional green ground wire that is tied in with the white wire (ground) in the circuit.
In this pic we see a close up of some of the soldered connections and the jumper wires. Notice the quality of the solder joints, shiny and smooth.
A few minutes with a soldering iron to make the final connections. Then the exposed solder joints are allowed to cool and wrapped in tape to protect them.
Here you can see the completed wiring and pick-up swap.
The lead wire connections to the pick-up taped to prevent accidental connections.
With the wiring completed, and the pick-guard assembly reconnected to the existing output jack and ground connections on the body, I carefully fit the pick-guard back into place, and do a quick amp test to check that everything is working. Oops! I had accidentally wired the bridge and neck pick-ups to the switch reversed, resulting in the lever switch operating backwards. This is exactly why I do that quick amp test before completely reassembling the guitar. Back to the bench, I do a quick switch of the two positive wires (the grounds are all connected together in this type of passive circuit and didn’t have to be switched). Then run another amp test, and with everything seeming to be working I reassemble the guitar.
The tools used to do the pick-up swap.
- Soldering Iron
- Solder
- Electrical Tape
- Wire Stripper and/or scissors
- Copper wire for leads
- A Multi-meter
- Screwdrivers
- Pliers or Socket Wrench
