When did Telecaster wiring change?
This wiring is referred to as the “modern" or “standard" Telecaster wiring and is still in use today. To understand why Tele wiring changed in 1967, it's useful to review some history.
Are Telecaster pickups wired in series or parallel?
On a stock Tele, the pickups are connected in parallel when you use them together, but if you run them in series instead, the resulting output is hotter and louder, and this makes it much easier to drive your amp into saturation. If you're craving burly Tele tones, series wiring will deliver.