By Chris DoughertyIf you're working on your hydraulic slideout system from Lippert Components, you may have come across the term "Trombetta." This is the name of a company that builds electrical components, and they manufacture the DC Contactor that operate hydraulic slideout and leveling systems.
So what do these contactors do? Well, basically, they're used to control the reversing the polarity of a DC motor, or in this case the hydraulic pump that moves your hydraulic slideouts or leveling jacks. When you push the switch in one direction inside the coach, the slideout room moves out. When you push the switch in the other direction, it comes back in. The contactor is fed voltage by the switch in a different manor depending on which way you push the switch, and this determines how the contactor will energize the motor (one way for out, or reverse for back in.)
The Trombetta contactor can be a point of malfunction for a slideout system, especially if it is exposed to the elements or road spray, leading to corrosion. Troubleshooting should include determining if the system is being fed adequate DC power (check the fuses!), and if the switch is operating correctly. If everything up to the contactor is working properly then check to see if there is any output from the contactor to the motor. Good voltage here may mean the motor is bad. Use a voltmeter set on DC Volts to check for 12 VDC throughout the system. This meter, set to Ohms, can also be used to test the switch and the contactor for continuity.
As a safety point, be sure to disconnect 12 VDC power at the source if you will be disassembling the system, to avoid short circuiting. Refer to the service manual for the system you are working on for more detailed service information.
Chris Dougherty is an RVIA/RVDA Certified Technician.