Where is the electronic spark control module on a 95 Yukon?

The Electronic Spark Control (ESC) module on a 1995 GMC Yukon isn't a single, easily identifiable module like some later vehicles. The spark control functions are integrated into the Powertrain Control Module (PCM), often called the Engine Control Module (ECM).

Therefore, you won't find a separate "ESC module." The PCM is usually located under the hood, often near the firewall. It's typically a fairly large, rectangular box with numerous connectors. You'll likely need to consult a wiring diagram specific to your Yukon's engine (e.g., 5.7L, 7.4L) to pinpoint its exact location. A repair manual for your vehicle will be the best resource for this.