RV Electrical Problems: 12V & 120V Troubleshooting Guide 2024

Short Answer

Your 2007 Holiday Rambler Admiral SE has a faulty connection or component between your auto transfer switch and the main electrical panel, likely caused by the repeated moving and vibration. Since 120V power reaches the main panel but your appliances and energy management panel aren't getting power, the issue is most likely a loose neutral connection, a failed breaker in your main panel, or damaged wiring between the transfer switch and distribution panel. The fact that everything works perfectly on generator power confirms your RV's internal wiring is fine - the problem is specifically with the shore power distribution after the transfer switch.

Understanding the Problem

The symptoms you're describing point to a classic shore power distribution failure that's common in RVs after being moved frequently. Your auto transfer switch is working correctly - it's detecting shore power and switching over from generator mode. However, somewhere between that switch and your appliances, the electrical connection is failing. This explains why your energy management panel is dark and why no 120V appliances work on shore power.

In your 2007 Holiday Rambler Admiral SE, the electrical path goes: shore power cord → auto transfer switch → main breaker panel → individual circuit breakers → your appliances. Since you've confirmed power reaches the main panel, the failure is likely at the main breaker itself or in the connections immediately after it. RV electrical systems are particularly susceptible to loose connections due to constant vibration and movement.

The fact that everything works perfectly on generator power is actually helpful - it tells us your RV's internal wiring, appliances, and most of the electrical system are functioning properly. The problem is isolated to the shore power distribution side only.

What You'll Need

• Digital multimeter (capable of 120V AC) - primary diagnostic tool
• Non-contact voltage tester
• Screwdriver set
• Wire nuts and electrical tape
• 12-gauge electrical wire (if needed)

Also helpful:

Safety equipment is crucial when working with 120V systems. Have a flashlight or headlamp ready since you may need to work in dark compartments. Consider having a basic electrical contact cleaner and some dielectric grease on hand, as corrosion in connections is common in RVs, especially in Florida's humid environment.

If you're not comfortable working with 120V electrical systems, this is definitely a job for a qualified RV technician. However, the diagnostic steps can help you understand the problem before calling for service.

How to Fix It

Start by turning off shore power at the pedestal, then turn off the main breaker and disconnect the shore power cord for safety. Ensure your generator is also off and disconnected - never have multiple power sources connected simultaneously during testing as this can damage your transfer switch and create safety hazards. With your multimeter, verify that you're getting 120V at the INPUT side of your main breaker (reconnect shore power temporarily for this test only, keeping the main breaker OFF, then immediately disconnect shore power again before proceeding). If you're not getting voltage there, the problem is between your transfer switch and main panel - likely a loose or corroded connection in that run of wire.

Next, turn the main breaker ON and check that you get 120V on the OUTPUT side, then turn it back OFF before making any connection inspections. If you have voltage on the input but not the output, your main breaker has failed. This is actually quite common in RVs due to the constant vibration and is a relatively inexpensive fix - expect to pay around $30-50 for a replacement 30 or 50-amp main breaker depending on your setup.

If voltage is present on both sides of the main breaker, check each individual circuit breaker that feeds your non-working appliances. Test both the input and output sides of each breaker. Pay special attention to the breaker that feeds your energy management system, as this controls many of your RV's electrical functions.

Look carefully at all wire connections in your main electrical panel, particularly the neutral and ground bus bars. Vibration from moving the RV repeatedly can loosen these connections. For neutral issues, you'll need to test voltage between hot and neutral at each circuit - if you're getting 120V hot-to-ground but not hot-to-neutral, this indicates a neutral connection problem that requires tracing the neutral path. Tighten any loose connections you find, but be careful not to over-tighten as this can damage the wire or connection points.

Leave It to the Experts

If you're not comfortable working with 120V electrical systems, or if the diagnostic steps above don't reveal an obvious problem like a failed breaker, it's time to call a qualified RV technician. Electrical problems can be dangerous if not handled properly, and in Florida's climate, you need your air conditioning working reliably.

Look for an RV service center that specifically mentions electrical expertise - not all RV mechanics are equally skilled with electrical diagnosis. Expect to pay $100-150 for diagnostic time, plus parts and labor for the actual repair. If it's a simple main breaker replacement, total cost should be under $200. More complex wiring issues could run $300-500 depending on what needs to be replaced.

Given that you've already had to cancel one trip, getting this diagnosed and repaired quickly is worth the investment. A qualified technician should be able to diagnose this type of problem within an hour and have you back on the road with reliable shore power for your Florida adventures.