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Lippert 378047 Door Switch - 3/8 Inch Diameter Replacement Slide-Out Switch
Lippert Components 378047 replacement 3/8 inch diameter door switch for RV slide-out and entry door applications, shown in product packaging
 
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: $55.55
Part Number: 378047
Manufacturer: Lippert

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Lippert Components OEM Part 378047 3/8" Diameter Lippert 378047 Replacement Door Switch -- 3/8 Inch Diameter

When a faulty door switch kills your slide-out signal, your lighting circuit, or your entry door sensor, replacing the switch is a quick fix -- if you have the right part. The Lippert Components 378047 is the correct 3/8 inch diameter switch for a wide range of Lippert-equipped RVs, covering slide-out rooms, entry doors, and storage compartment panels. This is a genuine Lippert OEM replacement that drops into the existing mounting hole without drilling or adapting.

The Right Switch for Lippert-Equipped RVs

Lippert Components is the dominant supplier of slide-out systems, entry doors, and chassis hardware across Class A motorhomes, Class C units, fifth wheels, and travel trailers. Because Lippert supplies so many OEMs -- including Forest River, Coachmen, Jayco, Keystone, Thor, and Heartland -- their small electrical components like this door switch appear across hundreds of model years and floorplans.

The 378047 is a momentary-contact plunger-style switch with a 3/8 inch diameter body, meaning it fits a standard 3/8 inch drilled or punched mounting hole. The switch is typically used in one of three roles: as a courtesy light trigger on entry doors or storage bays, as a position-sensing switch on slide-out rooms, or as an interlock in door-open warning systems. Identifying which role yours plays takes about 30 seconds with a multimeter -- either way, the 378047 is the OEM replacement.

3/8 Inch Body Diameter

Fits standard 3/8" mounting holes found throughout Lippert door frames, slide-out panels, and bay doors -- no redrilling or bushings needed.

Genuine OEM Part

Lippert part number 378047 -- the same switch spec'd by the factory, ensuring correct operation with existing wiring harnesses and control modules.

Momentary Plunger Style

Spring-loaded plunger design activates on contact and releases when the door or panel opens -- the standard configuration for RV courtesy and interlock circuits.

Broad OEM Fitment

Used across Forest River, Coachmen, Thor, Keystone, Heartland, and Jayco units built with Lippert door and slide hardware -- covers many model years.

Common Applications on Your RV

This switch shows up in several places depending on your rig's configuration:

  • Entry door courtesy light trigger -- plunger is depressed when the door is closed, completing or breaking the circuit to the interior courtesy lamp. When the switch fails, the light stays on or off regardless of door position.
  • Slide-out room position sensor -- some Lippert slide systems use a plunger switch to confirm the room is fully retracted before allowing travel-mode interlocks to clear. A failed switch can produce false "slide open" warnings on the dash or monitor panel.
  • Storage bay lighting -- exterior bay doors on Class A and fifth-wheel rigs frequently use a plunger switch to trigger an LED strip or incandescent lamp inside the bay. A sticky or corroded switch is the number-one reason bay lights stop working.
  • Door-ajar warning circuits -- some chassis and coach builders wire this switch into an audible or visual door-open alert. A failed switch causes a constant false alarm or disables the alert entirely.
Easy DIY Replacement
Swapping a plunger door switch is one of the most straightforward RV electrical jobs. Disconnect shore power or your battery disconnect, remove the two wires from the spade terminals (photograph them first), unthread the switch body from the mounting hole, thread in the new 378047, reconnect the wires, and test. Most installs take under 15 minutes with a nut driver and needle-nose pliers.

Diagnosing a Failed Door Switch Before You Order

Confirm the switch is the culprit before replacing it:

  • Set a multimeter to continuity or resistance mode.
  • Disconnect the two wires from the switch terminals.
  • Press the plunger manually and check for continuity -- a healthy normally-open (NO) switch will show continuity when pressed, open when released. A normally-closed (NC) switch will do the opposite.
  • If the switch shows no change in continuity regardless of plunger position, it is failed and the 378047 is your replacement.
  • Also inspect the plunger for physical sticking or corrosion -- penetrating oil can occasionally free a stuck plunger without full replacement.
Normally Open vs. Normally Closed Configuration
Lippert uses both NO and NC plunger switches depending on the circuit. The 378047 as supplied by Lippert is used in normally-open applications in most documented fitments -- meaning the circuit is open (off) at rest and closed (on) when the plunger is depressed. Verify your circuit's behavior before ordering if you are unsure. Your existing switch body is usually marked NO or NC near the terminals.

Installation Tips for Longevity

Maintenance and Installation Notes
  • Apply a thin coat of dielectric grease to the spade terminals before reconnecting wires -- moisture intrusion at unprotected terminals is the leading cause of premature switch failure in storage bays and entry doors.
  • Do not overtighten the switch body in the mounting hole. Finger-tight plus a quarter turn with a nut driver is sufficient -- the switch body threads are fine and can strip or crack if over-torqued.
  • If the switch is mounted in an exterior bay door, inspect the door seal around the mounting hole annually. Water wicking through a degraded seal will corrode the switch contacts even on a new unit.
  • Keep the plunger travel path clear of paint, caulk, and debris. A plunger that cannot fully extend will not open the circuit correctly, mimicking a stuck-closed failure.
Check Your Lippert System While You Are In There
If you are replacing a failed door switch, it is worth inspecting the wiring harness connector and the plunger strike plate at the same time. Worn strike plates cause the plunger to bottom out at an angle, accelerating contact wear. Lippert replacement strike plates and wiring pigtails are available separately if yours shows damage.

Part Identification

ManufacturerLippert Components (LCI)
Part Number378047
UPC848150042156
DescriptionDoor Switch, 3/8 Inch Diameter
Switch StyleMomentary plunger (push-to-make or push-to-break)

Physical Specifications

Switch Body Diameter3/8 inch (0.375")
Package Dimensions5.0" x 3.0" x 0.5"
Shipping Weight0.35 lbs
MountingThreaded body, single 3/8" hole mount
Terminal TypeSpade (quick-connect) terminals

Electrical Characteristics

Circuit Voltage12V DC (standard RV low-voltage circuits)
Typical Circuit TypeCourtesy lighting, position sensing, interlock
Contact ConfigurationNormally Open (NO) -- typical fitment

Fitment and Compatibility

Primary ApplicationRV entry doors, slide-out rooms, storage bay doors
Compatible Chassis/Coach BrandsForest River, Coachmen, Thor Motor Coach, Keystone, Heartland, Jayco, Fleetwood (Lippert-equipped units)
Slide System CompatibilityLippert electric slide-out systems using 3/8" door switch position sensors
RV ClassesClass A motorhome, Class C motorhome, fifth wheel, travel trailer
Mounting Hole Required3/8 inch diameter

What Is Included

In the Box1x Lippert 378047 door switch
Not IncludedWiring pigtail, strike plate, mounting hardware
Important Information -- Read Before Installing
  • Always disconnect shore power and engage the battery disconnect before working on any RV door switch wiring. Even low-voltage 12V circuits can trigger slide-out movement or other actuators if shorted during installation.
  • Verify your mounting hole is 3/8 inch diameter before ordering. A 1/4 inch or 1/2 inch hole is not compatible with this switch body without a bushing adapter.
  • Confirm the circuit polarity and contact configuration (NO or NC) of your existing switch before installing the replacement. Wiring an NO switch into an NC circuit will invert the function of the controlled device.
  • This switch is designed for low-current 12V DC circuits such as courtesy lights and sensor inputs. Do not wire it directly into high-current motor or actuator circuits.
  • This listing is for the switch only. The wiring harness, mounting bracket, and strike plate are not included and must be reused from the original installation or sourced separately.
  • If you are unsure whether 378047 is the correct part for your specific unit, cross-reference by your RV's VIN build sheet or contact Lippert technical support with your coach model and year for confirmation.


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