RV Wiring Diagnosis & Repair Near Me
Coast to Coast RV Repair provides mobile wiring diagnosis & repair service on-site at your campground or driveway across Florida - certified technicians, same-week scheduling.
Coast to Coast RV Repair provides mobile wiring diagnosis & repair service on-site at your campground or driveway across Florida - certified technicians, same-week scheduling.
Certified technicians. $299 service call. Same-week scheduling. Call (866) 887-1199.
Intermittent RV Wiring Faults - Why Load Testing is Mandatory
The most common wiring diagnosis error is testing circuits at zero load. A partial conductor break with 7 of 19 strands severed creates a fault resistance of 4 - 8 ohms. At zero current (no-load), Ohm's law means zero voltage drop across the fault - a multimeter reads 120V at the outlet and the circuit appears perfect. Under a 12A load, the same 4-ohm fault resistance drops 48V, leaving 72V at the outlet - below the operating threshold of most devices. Every wiring diagnosis at Coast to Coast starts with the load applied.
Ground Faults and Open Grounds in RV Wiring - GFCI Limitations
GFCI protection trips when current between the hot conductor and ground exceeds 5 milliamps - it is designed to prevent electrocution, not to protect against conductor faults. An open ground on a GFCI-protected circuit means the ground wire is missing or broken while the hot and neutral are intact. We test ground continuity with a Fluke 289 in ohm mode from the chassis neutral bus to the ground terminal at every outlet in the RV - resistance should be under 0.5 ohm on a 14 AWG ground wire run of 50 feet or less.
Water-Damaged Wiring Diagnosis - What Roof Leaks Do to RV Electrical Systems
A roof leak that reaches the 12V wiring harness begins degrading copper conductors within 48 hours of first contact. The failure mechanism is galvanic corrosion between the stranded copper conductors and the steel staples used to secure the wire run in the wall cavity. Corrosion resistance increases progressively - a 14 AWG conductor that was 0.002 ohm per 100 feet when new can reach 0.8 ohm or more per 100 feet after 12 months of wet-dry cycling in a roof leak path.
Also see: Electrical & Solar Services
This page covers wiring diagnosis & repair specifically. For the full range of electrical & solar services we offer, visit our Electrical & Solar service overview.
Case Study: A 14 AWG THHN wire in the exterior circuit run had a partial conductor break (7 of 19 strands severed) inside the PVC conduit stub at the rear roadside slide-out bay where the conduit flexed during slide extension.
RV: 2016 Coachmen Apex Ultra-Lite 215RBK • Location: Fort Wilderness Resort & Campground, Site 1200 • City: Orlando
Symptom: The owner reported that the exterior 120V receptacle on the driver-side rear worked intermittently - functioning for 30 - 90 minutes after plugging in then going dead, with no tripped breaker visible in the panel, and the bathroom GFCI outlet (which feeds the exterior circuit) still showing a green pilot light during the outage.
Diagnosis: Technician measured 120V at the bathroom GFCI feed terminals with no load (normal). Plugged a 1,500W space heater into the exterior receptacle and measured voltage drop from the GFCI feed to the exterior outlet - 118V at source, 11V at outlet under load, confirming a high-resistance series fault in the conductor.
- Load-Triggered Fault Confirmation: Plugged a Fluke 289 on AC volts across the exterior outlet and then loaded the circuit with a 1,500W space heater - voltage collapsed from 118V to 11V within 8 seconds, confirming a high-resistance series fault in the wiring, not a GFCI issue.
- Wire Tracing: Used a Sperry CS61200U circuit tracer to follow the exterior outlet circuit from the panel to the GFCI and then from the GFCI through the floor to the rear bay - identified the wire entering a 3/4-inch PVC conduit stub at the slide-out bay entry.
- Conductor Tension Test: Pulled both ends of the wire from the conduit, connected the Fluke 289 in milliohm mode with clip leads, and applied 2-pound pull tension to the wire mid-run - resistance jumped from 0.002 ohm to 4.7 ohm, pinpointing a partial strand break in the conduit flex zone.
- Wire Inspection: Cut back the wire at the conduit exit point and found 7 of 19 conductors severed cleanly inside the insulation jacket, consistent with repeated flexing at the conduit gland edge during slide extension.
- Wire Replacement: Pulled the damaged 14 AWG THHN from the conduit using a pull string and replaced it with a new 14 AWG THHN conductor, leaving 12 inches of service loop coiled at the conduit entry point to allow slide flex without conductor tension.
- Conduit Gland Protection: Installed a Heyco M1250 flex strain relief at the conduit entry to prevent the replacement wire from making hard contact with the conduit edge during slide travel.
- Load Test Sign-Off: Ran the 1,500W space heater from the exterior outlet continuously for 2 hours while operating the slide 20 cycles - voltage held at 117.8V - 118.1V throughout with no intermittent drop.
Outcome: The exterior outlet has functioned without interruption through 6 subsequent camping trips according to the owner's follow-up call.
Time on-site: 2 hours 40 minutes • Total cost: $299 service call + $28 wire and fittings + $245 labor • Dealer alternative: Coachmen dealer in Kissimmee quoted $385 diagnostic minimum, stated they would need the trailer for 5 business days to trace the intermittent fault.
“Three different shops looked at that outlet and said they could not find anything wrong. Your tech plugged in a space heater and found the problem in 15 minutes.”
Wiring Diagnosis Tools We Use On-Site
| Tool | Make/Model | Primary Use | Key Spec | Why We Use It |
|---|---|---|---|---|
| True-RMS Multimeter | Fluke 289 FVF | Milliohm continuity, AC/DC voltage, load testing | 0.025% basic accuracy, milliohm resolution | Detects partial-strand breaks invisible to cheap meters |
| Circuit Tracer | Sperry CS61200U | Trace live and dead circuits through walls and floors | 12 AWG - 3 AWG, 9V - 300V | Follows wire runs without opening every junction box |
| Clamp Meter | Klein Tools CL800 | Current measurement under load without breaking circuit | True-RMS, 600A AC/DC, 2kHz bandwidth | Verifies actual motor and appliance draw vs. breaker rating |
| Non-Contact Voltage Tester | Klein Tools NCVT-3P | Confirm safe-off before opening panels | 24V - 1000V AC detection | Required first step before any panel work |
| Wire Tracer | Klein Tools ET40 | Identify specific wire in multi-wire bundles | Distinguishes individual wires in bundles of 20+ | Critical for slide-out harness and converged wiring runs |
| Power Quality Analyzer | Fluke 435-II | Inverter THD measurement, harmonic analysis | THD to 0.1%, 50/60Hz | Catches degraded inverter output quality before it damages appliances |
Signs You Need Wiring Diagnosis & Repair
- ✓Always test circuits under a real load (1,000W minimum for 120V circuits, 10A for 12V circuits) before concluding a wire run is good - zero-load testing misses partial-strand breaks and high-resistance corrosion faults
- ✓Check the GFCI outlets in the bathroom, kitchen, and exterior locations on your RV - many exterior outlet circuits are downstream of an interior GFCI that is not labeled and resets outside the fault location
- ✓Look for green or black oxidation on any wire insulation visible in storage bays, junction boxes, or under the fridge - this indicates copper oxidation from a water intrusion event
- ✓After any roof repair or slide-out seal replacement, test all circuits in the affected zone under load for at least 30 minutes to catch corrosion-related intermittent faults before they fail at an inconvenient time
- ✓Inspect all ground bonding wires at slide-out joints and door frames - these flex with every slide cycle and the ring terminal crimp fatigues in as few as 500 cycles on aluminum-frame trailers
- ✓If you smell warm plastic or burning near a wall cavity during use, turn off the affected circuit at the panel immediately and call us before resetting it
Wiring Diagnosis & Repair - Pricing
Typical price range: $245 - $1,200
All calls start with a $299 service-call fee that covers the technician's trip to your location and the first hour of diagnosis. That $299 applies toward any repair you authorize - it is not an additional charge on top of the repair. Pricing shown is a national average range; your exact quote is provided in writing on-site before any work begins.
Wiring Diagnosis & Repair - Common Questions
Straight answers from our wiring diagnosis & repair service call log.
Why does my 120V outlet work when I plug in a phone charger but not when I plug in a space heater?
A phone charger draws under 1A. A space heater draws 12 - 13A. The difference in current reveals a high-resistance conductor fault that is invisible at low current but drops significant voltage at high current. This is the classic partial-strand break signature.
My electrician at home said the wiring looks fine - why does it keep failing?
Residential electricians are trained on stationary structures with rigid conduit and solid copper wiring. RV wiring is stranded copper routed through flexible conduit that bends with every slide movement and every bump in the road. The fatigue failure modes do not occur in residential wiring.
Can I just add a second GFCI outlet to protect an exterior circuit that keeps tripping?
No. Adding a second GFCI in series with an existing GFCI downstream creates nuisance tripping because both units monitor the same current and may trip at slightly different thresholds.
How long does wiring diagnosis take for an intermittent fault?
Simple intermittent faults typically resolve in 60 - 90 minutes on-site. Complex intermittent faults involving slide-out harnesses, water-damaged multi-circuit sections, or faults that only appear after 20+ minutes of operation can take 3 - 4 hours.
My RV has a previous owner wiring modification - is that a safety problem?
Potentially yes. The most common DIY wiring problems we find in used RVs: wire gauge undersized for the breaker protecting it, missing junction box covers leaving splice connections exposed, and unterminated wire ends in wall cavities.
More Electrical & Solar Services
Other specialized repairs under electrical & solar - all done at your location, no tow required.
Where We Provide Wiring Diagnosis & Repair in Florida
Coast to Coast RV Repair runs wiring diagnosis & repair jobs across these cities. Click your closest one for local-specific info, response times, and campground coverage.