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RVing message boards => Motorhomes => Topic started by: Lordismyshepherd on October 06, 2017, 12:21:41 PM

Title: Slide out safety switch or interlock
Post by: Lordismyshepherd on October 06, 2017, 12:21:41 PM
We have a 2001 Monaco Signature and just had the kitchen slide hydraulic cylinders rebuilt.  After they were reinstalled the tech says the coach won't stay running.  It will idle for a short time and then shut off.  If they prime the engine (Cummins ISM 500) it will start, ideal for a short period of time and shut off.  This problem did not exist prior to the removal and installation of the hydraulic cylinders.  I explained to him I am pretty sure there is a safety switch somewhere in the system because the slide will not go in or out when the motor is running. He feels it's a fuel pump issue.  He said he contacted Monaco and they one, only have fuel pump diagrams for the model year 2000 or 2002, and nothing for 2001 and two, the person he spoke with told him there were no safety switches connecting the slide out and fuel pump.  Anyone....
Title: Re: Slide out safety switch or interlock
Post by: ArdraF on October 06, 2017, 05:49:55 PM
We have a 2004 Monaco Executive.  There are some safety things built into ours.  We can't put slides in or out if the engine is running OR if an underbay is open.  I think the intent is to make sure you can't drive anywhere with the slides out or utility hoses still hooked up.  There is one caveat, however.  One time I was driving when an under bay door opened.  It's the style that opens under a slide and is horizontal to the ground when open which means it sticks out pretty far.  Luckily we didn't have any oncoming traffic and I was able to pull over to close it.  But the main thing is that I can't put the slides out if Jerry has already opened the utility bay door to start hooking up.  We also were instructed to turn the engine off before opening or closing the slides.  When we arrive at a site we get the air up, turn off the engine, and then put the slides out.  When leaving we air up, turn off the engine, retract the slides, and then restart the engine.  So I'm guessing you might have a normal situation but you'll have to experiment to find out for sure.

Title: Re: Slide out safety switch or interlock
Post by: Lordismyshepherd on October 08, 2017, 07:01:50 AM
Thank-you  ArdraF.  I passed along your information and not more than a couple of hours later I got a phone call from the technician.
He said they were able to keep the coach running.  He told me he thought there might have been an issue with fuel gelling in one of the filters because there was a puff of blue smoke and then it kept running.  I am not sure I am buying it.  I am thinking they followed your suggestions and did not want to admit they had no idea of how the safety systems work.  At this point I am just happy they were willing to listen.  Thank-you again for your help. It certainly saved us a lot of grief and aggravation.
Title: Re: Slide out safety switch or interlock
Post by: Gary RV_Wizard on October 08, 2017, 10:27:12 AM
It was fairly common back then to have a slide interlock with the ignition, but typically it would prevent starting the engine at all, not let it start and run awhile. If there is a concern about driving with the slide out, even a minute is risky. I don't think your problem is directly related to the hydraulics, but of course they may have inadvertently mucked up something in the process. The more common type of interlock prevents the slide motor from engaging while the engine is running, but that doesn't seem to be the case here.

[NOTE: late model coaches built to RVIA standards run the slides off the chassis power system and may require that the engine be running to deploy slides, so the thinking on this has changed since 2001.]

There would be no direct connection to the engine fuel pump in any case. Nor to the fuel lift pump that helps to prime the system for starting. Most diesels have a separate fuel control solenoid that would prevent fuel from flowing and thus prohibit the engine from running at all, and that is usually activated by the ignition switch +12v line. The engine is shut down by removing power from that solenoid and letting it close.
Title: Re: Slide out safety switch or interlock
Post by: ArdraF on October 08, 2017, 06:31:45 PM
You're welcome and even if it wasn't my suggestion that helped, we're happy for you that they got it running.  Along the same lines, most RV generators won't work if the fuel level drops below about 1/4 tank which leaves enough fuel for you to get to a fuel stop before you run out!  I hope it stays running.