A 2024 vehicle has roughly the computing power of a small business — 40+ electronic control units talking over CAN bus networks, controlling everything from the engine and transmission to the heated seats and the rear camera. When something goes wrong electrically, the symptom (a dead window, a phantom warning light, an intermittent gauge) rarely tells you where the actual fault is. Frank's Automotive in Seguin does proper electrical diagnosis — trace the circuit, identify the failure, fix it once.
What an electrical diagnostic involves
- Full-vehicle module scan — not just the engine. Body control module, transmission, ABS, airbag, infotainment, climate — many faults show codes in modules a basic scan won't read
- Wiring inspection — chafe points, melted insulation, rodent damage (a real problem, especially in vehicles parked outside), corrosion at connectors, damaged grounds
- Circuit tracing with manufacturer wiring diagrams — voltage drop tests, continuity, scope readings on signal lines
- Lighting — headlights, brakes, turn signals, interior, DRLs. Aftermarket LED-conversion troubleshooting where customers have done their own conversions
- Module replacement and programming — many modules require programming or coding after replacement; we have the tools for most makes
- Wire repair, not module-swap — we fix wiring when wiring is the problem, instead of reflexively replacing a $400 module
We write up what we found and what it costs before doing the work. Electrical can spiral if you're not deliberate; we're deliberate.
When to come in
- Intermittent dashboard lights — battery, ABS, traction, airbag, check-engine
- Power accessories not working — windows, locks, mirrors, sunroof, power seats
- Headlights or taillights dim, flickering, or dead
- No-start or hard-start with no engine mechanical symptoms (often ignition switch, starter relay, or security system)
- Battery drained overnight despite a healthy battery and alternator (parasitic draw — we use a current clamp to find the offending circuit)
- Gauges fluctuating or reading incorrectly
- Strange behaviors after a recent repair elsewhere (often a ground wasn't reconnected or a connector wasn't fully seated)
Why Frank's
ASE Certified, with the scan tools, scopes, and OEM-equivalent diagnostic software to read every major module on most modern vehicles. We have wiring diagrams for current-generation makes and we repair wiring rather than reflexively swap modules. Work covered by our 24-month / 24,000-mile warranty.
Tell us what isn't working, when it started, and what was most recently serviced — call (830) 379-4840 or request an appointment and we'll get you on the diagnostic schedule.