Electrical & Diagnostic Specialists in Lakeland, FL
Today's RVs and buses have dozens of electronic control modules managing everything from engine performance to slide-out operation to climate control. When something goes wrong, a generic code reader is not enough. You need technicians who understand the entire electrical architecture of your vehicle—not just one piece of it.
At Nationwide Haul, our 2026 diagnostic technology provides factory-level access to every module on your vehicle—chassis, engine, transmission, ABS, body controller, and living space systems. We read the data, interpret it correctly, and fix the root cause. No guesswork, no parts-swapping, and no sending you somewhere else because we only know half the vehicle.
Whether you are dealing with a dead battery bank, an inverter that will not switch on, a dashboard full of warning lights, or a multiplex control panel that has gone dark, our ASE-certified electrical specialists have the training and the tooling to get your RV or bus back to full operation.
Electrical & Diagnostic Services We Provide
Factory-Level Diagnostics
A generic OBD-II scanner reads a fraction of what your RV or bus has to tell you. Our shop runs 2026 diagnostic platforms purpose-built for heavy-duty and RV applications: Cummins INSITE for engine and aftertreatment analysis, Allison DOC for transmission fault codes and adaptive parameters, Freightliner ServiceLink for chassis body controller and multiplexed systems, Spartan SCS for Spartan chassis modules, and Ford IDS/FDRS for Ford-based motorhomes and cutaway chassis. We read every module on your vehicle—not just the engine. Active fault codes, inactive fault codes, and live parameter data give us a complete picture of what is happening before we turn a single wrench. That means accurate diagnosis the first time and repairs aimed at the root cause, not just the symptom.
Chassis Electrical
Chassis electrical problems can leave you stranded or create safety hazards on the road. Our technicians diagnose and repair wiring harness damage, corroded or heat-damaged connectors, alternator and starter motor issues, and chassis battery service including load testing and replacement. We trace and repair ground faults—one of the most common and most frustrating sources of intermittent electrical problems in any vehicle. Lighting system service covers headlights, turn signals, marker lights, brake lights, and clearance lights to keep you legal and visible. When you have an intermittent fault that no one else can find, our systematic circuit tracing approach and factory wiring diagrams give us the edge to locate it.
House Electrical (12V DC)
Your living space runs on a separate 12V DC system that powers everything from interior lights to water pumps to slide-out controllers. We service and repair converter/charger units from Progressive Dynamics, WFCO, and Magnum, diagnosing charging profiles and output stages to determine whether your converter is actually maintaining your battery bank properly. House battery bank testing covers lead-acid, AGM, and lithium (LiFePO4) technologies—each with different testing and charging requirements. We handle fuse panel diagnostics, 12V distribution wiring, battery disconnect switch operation, and parasitic draw testing to find the hidden current drain that kills your batteries overnight. If your lights are dim, your water pump is sluggish, or your batteries are dead every morning, we will find out why.
Shore Power & 120V AC
The 120V AC side of your RV powers air conditioners, microwaves, residential refrigerators, and every household outlet in the coach. When shore power is not reaching your systems, the problem could be the shore power cord and inlet, the transfer switch (automatic or manual), the breaker panel, or the internal distribution wiring. We diagnose and repair inverter/charger systems from Xantrex/Schneider, Magnum, and Victron—including units that will not invert, will not charge, or throw fault codes under load. GFCI outlet testing and replacement, breaker panel inspection, and 50-amp to 30-amp system diagnostics round out our AC service capabilities. If your air conditioner trips the breaker every time it kicks on, or your inverter shuts down when you run the microwave, we have the test equipment and the experience to sort it out.
Multiplex & Network Systems
High-end motorhomes and modern buses use multiplex wiring systems that replace traditional point-to-point wiring with a networked communication bus. Systems like Spyder controls (Tiffin), Firefly (REV Group), and Vegatouch multiplex platforms manage lights, slides, awnings, leveling jacks, and climate zones from a central touchscreen interface. When a node loses communication or the control panel goes dark, the entire coach can seem dead—even though the underlying components may be perfectly fine. Our technicians understand CAN bus diagnostics, network node addressing, and the communication protocols these systems use. We isolate faulty nodes, repair damaged network wiring, reprogram control panels, and restore full system operation. If your touchscreen shows errors, your slides will not respond, or your lights are stuck on, multiplex network diagnostics is where we start.
Solar & Energy Management
Solar power systems and energy management technology allow RV owners to camp off-grid with confidence—but only when every component in the chain is working together. We diagnose and service solar charge controllers, panel wiring and connections, and battery monitoring systems including Victron BMV series and Xantrex LinkPRO monitors. If your solar array is not delivering the watts it should, or your battery monitor shows inaccurate state-of-charge readings, we trace the issue from panel to battery and identify the weak link. We also service energy management systems (EMS) that control load shedding and power distribution, ensuring your RV draws power efficiently whether you are on shore power, generator, or solar.
Common Electrical Problems We Solve
Electrical issues in RVs and buses have a reputation for being mysterious, but most of them follow patterns our technicians have seen hundreds of times. Here are the problems that bring owners to our shop most often:
- Dead house batteries — parasitic draw draining the bank overnight, faulty converter not charging, or batteries at end of life
- Inverter will not switch on — fault codes, low battery voltage cutoff, internal component failure, or wiring issues between the battery bank and inverter
- Shore power not charging — damaged shore cord, failed transfer switch, tripped GFCI, or converter/charger malfunction
- Dashboard warning lights — check engine, ABS, transmission temperature, DEF system, and low voltage warnings that require factory-level scan tools to properly interpret
- Intermittent electrical failures — loose connections, corroded grounds, chafed wiring, and heat-damaged connectors that come and go with vibration and temperature changes
- Multiplex control panel errors — touchscreen frozen, nodes offline, lights or slides not responding to panel commands
- Lights flickering — poor ground connections, failing converter, loose neutral wiring, or overloaded circuits
- Slides will not operate (electrical cause) — controller faults, low voltage, broken wiring to the slide motor, or multiplex communication failure
- Generator not communicating with transfer switch — auto-gen-start failures, transfer relay not engaging, or wiring faults between the generator and the main panel
Why Electrical Diagnosis Requires Expertise
RVs and buses are fundamentally different from cars and trucks when it comes to electrical systems. Your vehicle has two complete electrical systems—a chassis 12V system that runs the engine, transmission, and drivetrain, and a house 12V/120V system that powers the living space. These two systems interact through transfer switches, converters, inverters, and battery isolators. Add multiplex networking on top of that, and you have a level of electrical complexity that defeats most general mechanics and even many dedicated auto electricians.
Our technicians understand both sides of the equation and, critically, how they interconnect. A problem that presents as a house electrical failure might actually originate in the chassis system, or vice versa. A multiplex fault can masquerade as a mechanical slide-out problem. Without the training to see the whole picture and the diagnostic tools to confirm it, you end up replacing expensive parts that were never the problem. At Nationwide Haul, we diagnose first, confirm with data, and then repair with precision.
Why Choose Nationwide Haul
- 2026 Factory-Level Diagnostic Tools — Cummins INSITE, Allison DOC, Freightliner ServiceLink, Spartan SCS, Ford IDS/FDRS, and more. We invest in the same platforms the manufacturers use.
- We Read EVERY Module — not just the engine. Transmission, ABS, body controller, multiplex, leveling, generator—we scan the entire vehicle to find what others miss.
- ASE-Certified with Electrical Specialization — our technicians hold advanced electrical and electronics certifications and receive ongoing training on the latest RV and bus platforms.
- We Fix the Root Cause — no parts-swapping, no guesswork. We use data from the diagnostic scan to identify the actual failure, confirm our diagnosis, and make the repair right the first time.
- Transparent Diagnostic Reports — you receive a detailed report showing exactly what we found, what it means, and what we recommend. No mystery invoices, no hidden charges, and no work performed without your approval.