RV Repair on the Road - Replacing Selenoid

A few posts back, I mentioned that our solenoid was kind of giving us intermittent grief. Sometimes it would work, sometimes it wouldn't. It's function is to charge our two 6 volt house batteries, (for the 12 volt things in the camper), while driving down the road from the engines alternator. 

We can also charge those batteries by running the generator, or hooking up the solar panels, or by being plugged in at a campground that offers a power post.

So it wasn't extremely necessary to change it immediately, we could get by without it. But it is the easiest method of charging the batteries while driving. Then when you stop, they are fully charged. Easy peasy! 

We had a nice stretch of 4 days to sit back and relax at a campsite. Yes, believe it or not we actually do relax once in awhile.

But back along the way in upstate New York, we did manage to find the replacement solenoid at an O'Reilly's. Along with a couple extra tools and a special socket for removing the seat. Because don't you know, the solenoid is hidden underneath the passenger seat on this Mercedes-Benz Sprinter chassis. 

Ironically, because this part is known to fail, we had preemptively ordered one a few weeks before we left Oconto. But the shipment had been delayed twice, so it did not arrive in time before our trip. So when we get home, we will have to return that one. Too bad though, it was half the price of this one for the same part!

Oh well, at least we got it on the road and got the right part. It's called Cole Hersee 24213. 

There are very specific steps to changing this out. The solenoid itself is probably just a 10-minute job. But the prep work is what you have to do to be sure you don't wreck anything in the process. Especially when messing with electricity!!! 

First is to disconnect the driving battery for the diesel engine. The battery itself is hidden in a panel underneath the floor of the driver's seat area. But instead of removing the entire floor panel, they put in this handy dandy battery disconnect cable with a push button and a lug that's up near the foot throttle pedal on the driver's side. 

 

Next step is to be sure that you are completely unplugged from any electrical power at the post. Also, that bears in mind that you don't have the generator running either. 

(P. S. That is our Progressive Industries 30 amp Electrical Management System that we padlock to the post anytime we plug in. It protects all of the delegate electrical systems on board from any miswired, low voltage, loose ground or power surges) 

The third source of power that needs to be removed are the cables off the house batteries that are located underneath our entry step.  We just recently installed these, they are two Trojans 6-volt golf cart batteries hooked in series. The two 6 volts combine to make 12 volts. 6 volt batteries are better than 12 volts, because the plates are further apart and they take a charge better and don't draw down as fast. Oh well, back to the solenoid replacement. 

Now that all sources of power have been removed, it's time to take off the passenger seat. This took a special torque socket which is star shaped. By swiveling the seat at a 45° angle on the base, it's easier to reach the bolts.

We set the seat back carefully on our entry rug of the camper portion so the brackets underneath didn't destroy any of our flooring. Now Steve could access all of the wiring that's hidden underneath the passenger seat. 

He had the most adorable assistant, she was right there ready to hand him the tools as needed. Actually, I think she was upset with him because he was kneeling on her bed right at the foot of the passenger seat!

The old solenoid is attached to this long bracket. It's easier to remove the entire bracket to get the solenoid loose.

Once he had those two bolts out, from there it was easy to just transfer over each group of wires from the posts of the old solenoid over to the new solenoid. The only difference is, the old one just used the bracket as a source of ground. That's not always so reliable. The new solenoid has an additional center post on it, made specifically to become a ground. So the two original white ground wires are now screwed right to the solenoid instead of the bracket. 

In no time at all he was completely done! Everything put back where it belonged and everything tightened up where it needed to go. The seat was back on and now it was time to run our test.... we started the engine and held our breaths.

YAYYYYYY

IT'S CHARGING!!! 

Another job well done by my darling Steveio. He works so hard to keep us rolling down the road.