HWH Spacemaker Slide Motor Runs But Won't Extend: Complete RV Repair Guide

Tools & Parts Needed

Find these on Amazon: Digital Multimeter , Hydraulic Fluid , Contact Cleaner

The Quick Fix

When your HWH Spacemaker hydraulic slide motor runs but won't extend, you're likely dealing with a faulty extend solenoid, hydraulic leak, or safety lock issue.

What You Need

• Digital multimeter
• Basic hand tools
• Flashlight or work light
• Hydraulic fluid - ATF Dexron III or equivalent (if needed)
• Wire brush or contact cleaner
• Safety glasses

The Fix

1. Verify solenoid electrical operation: Typical HWH solenoid resistance should be 2-4 ohms - check manufacturer specs for your model, but test the solenoid under load. First verify 12V power at the solenoid terminals with the extend switch pressed, then test resistance. You should hear/feel the solenoid click when powered.
2. Check solenoid valve operation: Check if the extend valve has a manual override and test it first. Even if electrically sound, the solenoid valve itself may be stuck. Try gently tapping the solenoid body with a wrench handle while activating the extend function.
3. Inspect hydraulic connections: Look for leaks around the slide cylinder, hydraulic lines, and solenoid valve. Even small leaks can prevent proper extension under load.
4. Test safety lock system: Although visually retracted, safety locks can malfunction internally. Disconnect the safety lock solenoid temporarily and test slide operation. WARNING: Before disabling safety systems, ensure RV is on level ground, properly stabilized, and use mechanical blocking to prevent unexpected slide movement. Never work near or under an unsecured slide.
5. Check hydraulic fluid level: Low fluid in the reservoir can cause the pump to cavitate, producing motor noise without hydraulic pressure.
6. Verify pump pressure: If possible, check system pressure at a test port. HWH systems typically operate at 3000-3500 PSI for slide operation.

Understanding the Issue

Since your extend solenoid shows 1.2 ohms, the coil appears functional, but if you're also seeing open circuit behavior, this indicates intermittent connection issues or a problem with valve operation.

Solenoid valve sticking: The most frequent issue is debris or corrosion preventing the solenoid valve from opening fully. This allows electrical operation but blocks hydraulic flow.

Internal hydraulic leaks: Worn seals in the slide cylinder can create internal bypassing, where fluid circulates without creating extension force.

Safety lock malfunction: Even when visually retracted, safety locks can bind internally or have faulty limit switches that prevent slide operation.

Contaminated hydraulic fluid: Dirty or old hydraulic fluid can cause solenoid valves to stick and reduce system efficiency.

Know When to Call for Backup

Contact an RV hydraulic specialist if you encounter:

• System pressure testing requirements
• Hydraulic component replacement beyond solenoids
• Slide cylinder removal or rebuilding
• Multiple system failures affecting leveling and slides
• Electrical issues in the HWH control module

Professional diagnosis is especially important if the slide is partially extended and won't move in either direction.

Preventive Measures

Maintain your HWH Spacemaker system by:

• Operating slides monthly to prevent solenoid valve sticking
• Changing hydraulic fluid every 3-4 years or per manufacturer schedule
• Keeping hydraulic reservoir clean and properly filled
• Lubricating slide mechanisms and safety locks annually
• Avoiding slide operation in freezing temperatures

Regular maintenance prevents most hydraulic slide failures and extends component life significantly.