Dear RV Doctor:
I desperately need your input. I have a 1998 5th wheel RV with a slideout living room. My problem is that there must be a relay somewhere that is sticking when I attempt to close the slideout. I have talked to numerous RV repair shops, even the factory itself, and no one can help me.
When it is coming in, it does not want to stop when I release the switch. The In-and-Out switch is okay. It has a DeWalt hydraulic pump that operates the slideout. It is one that you can electrically bring the slide in or you can manually pump it in. Could the pump itself have the relay inside of it? Your help will be most appreciated. —J.R.M, USAF Retired
Without knowing the brand and model number of your particular slideout drive mechanism, it’s hard to tell with 100% certainty what the problem might be, but it sounds like the hydraulic solenoid valve itself may be sticking. The battery switch solenoid might be mounted right on the pump itself. This was typical back then. It will likely be cylindrical and silver in color as well. It is wired between the coach battery and the pump motor and is activated by the slide switch. Such solenoids had a tendency to stick as they aged.
My recommendation would be to locate the pump and then identify the solenoid. It should be a generic battery-type solenoid, so you can get a replacement at your local auto parts or RV store. Just make sure the replacement is made for heavy-duty applications. They are inexpensive, so if you are not adept at bench testing the solenoid itself, I recommend you replace this part first and see if that eliminates your problem.
If this does not fix the problem, then I suspect a hydraulic valve spool or another of the solenoids is sticking. This could be due to dirt stuck in the valve. In this case, you will have to take your coach to an experienced RV service facility to inspect, clean, and/or replace these pump components. It takes specific expertise to perform services on the internals of the pump assembly, unfortunately.
To read more from Gary, be sure to visit his website, The RV Doctor.