Jayco Precept Windshield Wiper Motor Troubleshooting & Repair Guide

Quick Take

Your Jayco Precept 29V's intermittent wiper issue commonly includes a faulty wiper control module, not the motor itself. While Ford mentioned a 2-speed motor limitation, modern wiper systems use electronic control modules to manage both speed and interval timing functions with standard 2-speed motors, so the issue is likely in the control circuitry rather than motor compatibility. The fact that your wipers move 5-6 inches (arm travel distance) and stop mid-cycle without returning to park position is a classic symptom of a failing wiper control module or timer relay, not a motor speed compatibility issue. Since your RV dealer has already replaced the motor and control board without success, and Ford tested the switch assembly as good, the problem likely lies in the wiper delay module or a wiring issue between the control board and the motor that's specifically affecting the interval circuit.

The frustrating back-and-forth between your RV dealer and Ford is unfortunately common with Class A motorhomes built on Ford chassis. However, since this is a newer model that failed within two months of ownership, this should definitely be covered under warranty. The key is identifying which component is actually at fault so the correct dealer can address it under your extended warranty coverage.

Common Causes

Based on your specific symptoms and the repairs already attempted, several components could be causing your intermittent wiper malfunction. The most likely culprit is the wiper delay control module, which is separate from both the main wiper motor and the dash-mounted control board your dealer already replaced. This module, typically located near the wiper motor assembly, controls the timing circuits for intermittent operation and the park position function.

Another strong possibility is a wiring harness issue specific to the interval timing circuit. Since normal and fast speeds work correctly, the main power feeds to the motor are intact. However, the interval function requires additional control wiring between the control module and motor that could have been damaged during the original failure or subsequent repairs. Water intrusion could have corroded specific connector pins or created intermittent short circuits.

The wiper motor's internal park switch could also be defective. This switch tells the control system when the wipers have returned to their home position. If it's not functioning correctly, the control module won't know when to stop the wipers during interval cycles, causing them to halt mid-sweep. This would explain why the wipers move partially then stop without completing their cycle or returning to park position.

Ground connection problems are another frequent cause of these symptoms. Wiper systems rely on multiple ground points, and corrosion or looseness at any of these connections can cause erratic operation. The interval timing circuits are often the first to be affected by poor grounding because they require precise voltage references to function correctly.

Preparation

SAFETY WARNING: Always disconnect the battery negative terminal before working on any electrical components. Wear safety glasses and insulated gloves when testing electrical circuits. Never work on wiper electrical systems during wet conditions or with wet hands.

Before proceeding with any diagnostic work, gather all documentation from the previous repair attempts. You'll need the part numbers of the wiper motor and control board that were replaced, along with any diagnostic notes from both the RV dealer and Ford service department. This information will help avoid duplicating unsuccessful repairs and identify which components have already been ruled out.

Locate your Jayco Precept's electrical schematic from your Ford chassis documentation, as detailed wiper system diagrams typically come from the chassis manufacturer rather than Jayco's owner's manual. The wiper system diagram will show the relationship between the dash switch, control board, wiper delay module, and motor assembly. Pay particular attention to the wire colors and connector locations, as these will be essential for proper diagnosis.

You'll need basic electrical testing equipment including a digital multimeter capable of measuring both DC voltage and continuity. A test light can also be helpful for quick power and ground verification. If possible, obtain a wiring diagram specific to your Ford chassis model year, as Ford sometimes makes running changes that aren't reflected in the RV manufacturer's documentation.

Ensure you have access to the wiper motor assembly, which on the Precept 29V is typically located behind the driver's side dashboard or in the engine bay area. You may need to remove interior panels or engine covers to access all components. Have replacement fuses available, as some diagnostic procedures may require fuse removal and reinstallation.

Document the current wiper behavior with a cell phone video if possible (this will require temporarily reconnecting the battery and turning on the ignition while following proper safety procedures). Record exactly how far the wipers travel before stopping, whether they attempt to return to park position, and any variations in behavior between different interval settings. This documentation will be valuable when communicating with service departments or warranty administrators.

Repair Steps

SAFETY WARNING: Ensure the ignition is off and battery is disconnected before removing any electrical connectors. Use proper lockout/tagout procedures if working in a shop environment.

Start by locating and inspecting the wiper delay control module, which is often a small rectangular box mounted near the wiper motor or behind the dashboard. On Ford chassis, this module may be integrated into the Generic Electronic Module (GEM) or Body Control Module (BCM), but many RV manufacturers add their own aftermarket delay modules. Check all electrical connections to this module, looking for corrosion, looseness, or signs of water damage from the original sleet storm incident.

Test the power supply to the wiper delay module using your multimeter. With the ignition on and wipers set to an interval position, you should see battery voltage (approximately 12.6-14.4 volts) at the module's power input terminal. If voltage is absent or significantly low, trace the power feed back toward the fuse box, checking fuses and relay connections along the way. Many wiper systems use multiple fuses - one for motor power and separate fuses for control circuits.

Verify the ground connections for the entire wiper system. Use your multimeter to check continuity between the wiper motor housing, control module chassis, and a known good ground point on the vehicle frame. Resistance should be less than 1 ohm for all ground paths. Clean any corroded ground connections with electrical contact cleaner and fine sandpaper, then apply dielectric grease to prevent future corrosion.

Test the park switch function within the wiper motor assembly. With the wipers in their current stopped position (5-6 inches across the windshield), use your multimeter to check for continuity across the park switch terminals in the motor connector. The switch should show continuity only when the wipers are in the full park position. If the switch shows continuity in the mid-travel position, the internal park mechanism is likely damaged and the motor may need replacement with the correct part for your model (verify with dealer).

Check the interval timing signal from the control board to the wiper delay module. This typically involves measuring a pulsing voltage signal that varies in frequency based on the selected interval setting. With the wipers set to the fastest interval setting, the timing signal should pulse more frequently than on slower settings. At the test interval position, you should see voltage pulses every 3-5 seconds. Slower interval settings should show proportionally longer pulse intervals. If no pulsing signal is present, the issue may be in the replaced control board or its programming.

Inspect all wiring between the control components for damage, corrosion, or loose connections that could affect interval operation. dash-mounted control switch and the wiper motor assembly. Pay particular attention to areas where wires pass through firewalls, around hinges, or near heat sources. Flex all wire harnesses while monitoring circuit continuity to identify intermittent connection problems. The interval control circuit often uses smaller gauge wires that are more susceptible to damage than the main motor power feeds.

If all electrical connections and signals test correctly, the problem may be mechanical within the wiper motor assembly. Remove the wiper arms and test motor operation without the mechanical load of the wiper linkage. If the motor completes full cycles without the wiper arms attached, the linkage may be binding or the motor may lack sufficient torque for your specific application. This would support Ford's claim about motor specification, though it doesn't explain why the original motor worked correctly before the sleet storm failure.

Consider the possibility of software or calibration issues if your RV uses an electronic control system. Some newer motorhomes require initialization or calibration procedures after component replacement. Check with Jayco technical support for any specific programming requirements for the 2025 Precept model. The control board replacement may have reset parameters that need to be re-established for proper interval operation.

When to Get Help

Given that this is a 2025 model under warranty that failed within two months of ownership, you should escalate this issue to both Jayco customer service and your extended warranty provider immediately. Document all repair attempts and clearly state that neither the RV dealer nor Ford has successfully resolved the problem despite multiple component replacements. Request involvement from both manufacturers' technical support teams to develop a coordinated repair approach rather than continuing the current back-and-forth pattern.

If electrical testing reveals complex wiring problems or control module programming issues, seek assistance from a shop that specializes in both RV electrical systems and Ford chassis components. Some independent RV service centers have technicians trained on both sides of the coach/chassis divide and can provide more comprehensive diagnosis. The cost of professional diagnosis may be worth avoiding further unsuccessful parts replacement.

Contact Jayco directly if you suspect the wiper system design or component specification is inadequate for the application. As a 2025 model, this could represent a design issue that affects other units and may warrant a technical service bulletin or recall. Jayco engineering support can provide definitive specifications for the correct wiper motor and control components for your specific coach configuration.

Consider involving your state's RV dealer licensing authority or lemon law provisions if the warranty repair process continues to stall. A 2025 RV with a basic safety system failure that cannot be resolved by authorized dealers may qualify for replacement or buyback protection. Document all communication with dealers and manufacturers to support any potential legal action.

If you need immediate wiper functionality for safe driving, some RV owners have successfully installed aftermarket universal wiper control modules as temporary solutions. However, ensure any modifications won't void your warranty coverage, and have all aftermarket components removed before presenting the coach for warranty service. The goal should be getting the original equipment properly repaired rather than implementing workarounds that may complicate the warranty claim process.