I've been troubleshooting persistent battery drain issues on my Thor Outlaw RV and have identified the salesman switch as the primary culprit. Despite being marketed as a battery disconnect, this switch fails to eliminate parasitic draw completely while simultaneously disconnecting the batteries from the charging system when on shore power.
The design creates a problematic scenario: batteries continue draining through various circuits even when 'disconnected,' but they cannot receive charge from the converter. This results in dead batteries after extended storage periods, particularly when parked indoors where solar charging is unavailable.
I'm experiencing about a 50% probability of completely dead batteries, where they're disconnected from the converter and lack sufficient power to even reconnect to the charging system. The indicator light provides no reliable signal about the switch's actual position, making it impossible to track battery connection status.
What are the most effective solutions for addressing this flawed disconnect system? Are there proven workarounds that other Thor Outlaw owners have implemented, or should I be looking at bypassing this switch entirely?
Salesman battery disconnect switches are flawed - they leave parasitic drains while disconnecting charging. Add true manual disconnect at batteries or use battery maintainer during storage. Many owners simply ignore the switch entirely.
you've hit the nail on the head - the "salesman switch" (battery disconnect solenoid) in your Thor Outlaw is indeed problematic, but it's not completely worthless when properly understood and maintained. Your frustration is shared by countless RV owners because Thor's implementation has several design flaws: the parasitic drain you're experiencing, the confusing indicator light that doesn't reflect actual battery connection status, and the potential for the solenoid to get stuck in the disconnect position when batteries are too low. The switch is supposed to isolate your house batteries from 12V loads while maintaining the charging circuit from your converter, but many Thor units have wiring issues that prevent this from working correctly.
The primary issue with your Thor's battery disconnect system stems from poor wiring design at the factory. Many Thor Outlaw models have the disconnect solenoid wired incorrectly, where it actually disconnects the batteries from the converter/charger when activated, opposite of what it should do. This creates the exact scenario you described - batteries dying while on shore power because they're disconnected from the charging source.
The phantom drain you're experiencing typically comes from several sources that remain connected even when the disconnect is "on": the CO detector (hardwired for safety), the LP gas detector, the inverter standby circuits, and often the slide-out control modules. These can collectively draw varying amounts of current continuously, which will kill house batteries in several days depending on their capacity and the actual current draw.
The indicator light confusion occurs because the red light shows power to the solenoid coil, not the actual connection status of your house batteries. When on shore power, the light stays illuminated regardless of whether your batteries are actually connected to the 12V distribution panel, making it nearly impossible to determine the actual switch position.
Temperature also affects solenoid operation - in cold weather, low battery voltage combined with the solenoid's power requirements can create a situation where there's insufficient power to energize the coil and reconnect the system, leaving you completely dead.
SAFETY WARNING: Before performing any electrical work, disconnect shore power at the pedestal and turn off your main breakers. Always disconnect the negative battery cable last when connecting and first when disconnecting 12V systems. Improper electrical work can result in fire, electrocution, or equipment damage. If you're not comfortable with electrical troubleshooting, consult a qualified RV technician.
Before modifying or bypassing your disconnect system, you'll need a multimeter, basic hand tools, and wire strippers. Most importantly, take photos of your existing wiring before making any changes. Locate your battery disconnect solenoid - it's typically mounted near the batteries or in the front storage compartment, and looks like a rectangular relay with heavy gauge wires connected to it.
Test your current parasitic drain by disconnecting the negative battery cable and connecting your multimeter in series between the cable and battery terminal, set to measure DC amps using the 10A input jack (not the mA jack). Start with the highest amp range on your meter and work down to prevent meter damage from unexpected high current draws. With everything off and the disconnect switch in both positions, you should see the actual current draw. Acceptable draws are typically 50-85 milliamps for most RVs, but can vary by model and installed equipment. Excessive drain will be apparent when compared to manufacturer specifications for your specific components.
Identify all the circuits that remain hot when the disconnect is activated. This usually includes safety devices (CO/LP detectors), the inverter, and sometimes poorly wired slide controls or entertainment systems. You'll need to determine which of these drains are acceptable (safety devices) versus problematic (entertainment systems that should be switched).
The most effective solution is to rewire the disconnect solenoid properly. The large positive cable from your batteries should connect to one large terminal on the solenoid, and the main 12V distribution should connect to the other large terminal. Use appropriate wire gauge and fuse/breaker ratings per manufacturer specifications for your system's amperage requirements. The small trigger wire should be connected so the solenoid energizes (closes) when the switch is in the "on" position, keeping batteries connected to your loads and charger.
Install a proper battery monitor with a shunt to accurately track your battery state of charge and current draw. This eliminates the guesswork about whether your batteries are charging or discharging. Popular options include battery monitors such as Victron BMV series, Bogart Engineering TriMetric, or similar quality units, which will show you exactly what's happening with your power system.
For the parasitic drain, install individual switches for non-essential loads that are currently bypassing the main disconnect. Entertainment systems, unnecessary lighting circuits, and some slide controls can be switched independently. This requires running switched power feeds to these devices rather than having them on unswitched "hot" circuits.
Consider upgrading to a quality marine-grade disconnect switch which has clear on/off labeling and more reliable operation than the factory solenoid. Wire it to disconnect everything except the converter charging circuit and essential safety devices. This gives you true control over parasitic drains while maintaining battery charging capability.
Add a separate battery tender pigtail that bypasses all switches, allowing you to connect an external charger directly to the batteries when the RV is stored. This provides a backup charging method regardless of switch positions or solenoid failures and ensures reliable battery maintenance during extended storage periods.
Call a qualified RV technician if you're not comfortable working with 12V electrical systems or if you discover more complex wiring issues than expected. Many Thor units have additional problems like incorrect fuse panel wiring or improperly installed inverter connections that require systematic troubleshooting.
Professional help is also recommended if your testing reveals excessive current draws that you can't identify, or if you have a complex system with multiple inverters, solar controllers, or lithium battery management systems. These components can interact in unexpected ways that require experience to diagnose properly.
If your batteries are frequently dying despite addressing the disconnect issues, have them professionally tested. Batteries that have been repeatedly deep-discharged may have permanent damage, and continuing to use them will lead to ongoing frustration with your power system regardless of how well you fix the disconnect problems.
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