Motorhome Won't Start at the Campsite
Checkout is at eleven and the coach will not crank. The chassis battery, disconnect switch and solenoid checks that solve most campground no-starts.
Four days at a campground near Navarre or Pensacola Beach, the slides are in, the water is disconnected, and the coach will not start. Sometimes it clicks. Sometimes the dash lights up and nothing else happens. Sometimes there is no dash at all. It is one of the most common RV calls on the panhandle, and most of the time the cause is a battery that was fine when you arrived and is not fine now.
Here is how to work through it in the order that actually finds the problem.
Why the chassis battery dies while you are parked
On most motorhomes the chassis batteries and the house batteries are separate, and the house batteries are the ones that get charged by shore power. The chassis battery sits there. Meanwhile the chassis has small loads that never stop: the engine computer's memory, the radio, a dash camera, an aftermarket alarm, sometimes a step or a fan that was wired to the wrong side. Four days of that on a battery that was already tired, in the heat, and there is nothing left to crank a diesel.
Some coaches have a charging relay that lets shore power charge the chassis battery too. When it fails, or when it is not there, the chassis battery has no help.
The first five checks
- Battery disconnect switches. Many coaches have one for the house and one for the chassis. If the chassis disconnect is off, nothing will happen at the key. Find both and make sure they are on.
- The boost or battery-combine switch on the dash. It ties the house batteries to the chassis batteries for starting. Hold it and try the key. If the coach starts, the chassis batteries are the problem.
- The transmission selector. On many coaches the engine will not crank unless the selector is in park or neutral. A selector that is not fully seated is a common no-crank.
- Look at the chassis batteries. Corroded terminals, a loose clamp, or a battery that is bulging or hot. Clean and tighten before anything else.
- Listen at the key. A single click is usually the starter solenoid with low voltage. Rapid clicking is a very low battery. No click and no dash is a disconnect, a fuse, or a dead battery.
If the coach starts on the boost switch, do not just drive off. The chassis battery is either bad or something is draining it, and the next stop will be the same problem without a campground around it.
When the batteries are fine and it still will not crank
Then it is the starting circuit. A neutral safety switch on the transmission, a starter relay, a corroded cable end, or the starter itself. Diesel coaches also have a starter interlock tied to the air system on some chassis. The voltage drop test we described for trucks in Bad Grounds and Cables applies exactly here, and it finds a lot of coach no-starts that get blamed on the starter.
Fuel is the other one, on a coach that cranks but will not fire. A diesel that sat for a while can lose prime, especially if the fuel filter is due or the tank was run low. A gas coach that cranks and does not fire is usually fuel pump or ignition, and it needs a look.
The jump start
A diesel pusher will not jump off a car. It needs a real battery bank or a proper starting unit, and the connections need to be made at the right place, which is not always the battery terminals on a coach with a remote battery bay. Hooking a jump to the wrong point on a modern coach can take out the engine computer or the multiplex wiring. We covered the method in Jump Starting a Heavy Truck Without Wrecking Something. The same rules apply and the stakes are higher.
What the crew does at the campground
Test the chassis batteries under load, check the charging solenoid and the alternator output, check the cable ends, and figure out what drained the battery. Replace batteries on site if they are done, replace a failed cable or relay, and if a parasitic draw is the cause, find it before the coach leaves. Get the coach started, then make sure it will start again at the next stop. Campgrounds, storage lots, and driveways across the panhandle are all normal RV service calls, and we come to the site rather than making you find a way to move the coach.
Keeping it from happening next trip
Know where both disconnects are and use the chassis one when the coach sits. Check whether your coach charges the chassis battery on shore power; if it does not, a small maintainer solves it. Start and run the engine for a while during long stays. And replace chassis batteries on condition, not on failure. A battery that cranked slowly on the way in is telling you something. Our post on RV Generator and Battery Issues covers the house side of the same problem.
Frequently asked questions
Can I jump a motorhome from the house batteries?
If the coach has a boost or combine switch, that is what it does. Use it. Do not run your own cables between battery banks unless you know exactly what you are connecting.
The dash is dead but the house has power. What is that?
The chassis side has no voltage. Chassis disconnect off, a dead chassis battery, or a blown main fuse or fusible link on the chassis side.
Can you replace motorhome batteries at a campground?
Yes. Chassis and house batteries are replaced on site, wherever the coach is parked.
The coach started fine yesterday. Why not today?
Because yesterday it had a little more in the battery than it needed, and today it has a little less. Batteries fail on the day they cross that line, and heat and sitting bring the day closer.
Coach will not start at the campsite? Call Duckett Roadside Repair at (850) 495-0366. Dispatch is answered 24 hours a day and the crew comes to the site.