Lights Not Working in Jayco Camper Trailer: Troubleshooting The Most Common Causes

In this article I’ll help answer a question that pops up nearly every day: Why aren’t my Jayco camper’s lights working (even though I have power everywhere else)?

We’ll cover the most common causes AND a basic fault-finding process.

Let’s get started:

1. Check if you still have 12V power in places other than the roof

Jayco camper trailers have 2 separate electrical circuits:

• 240V for things like the microwave and power points
• 12V for lights, the gas cooktop piezo igniter, and USB ports

So the simple test here is:

Is your external light and stovetop ignitor still working?

If the answer is ‘NO’ then it’s not just your lights, you have a 12V supply problem

(skip to Step 7)

If the answer is ‘YES’ then now we’ve narrowed it down to that part of the 12V circuit…

2. Check the lever on the roof safety kill switch

Jayco camper trailers have a roof safety kill switch:

When the roof is packed down the metal lever is depressed. This pushes in the white button which cuts power to the roof

This is so that if the lights are accidentally left on they don’t set the canvas on fire

The most common reason for lights not working:

The metal lever often gets caught on the canvas and doesn’t let the white button pop out

So you might just need to check it here:

On our Jayco Swan the metal lever has fallen off the switch at some point. Handy.

Because this is one of the most common causes of lights not working, one of these is on our list of Our Jayco Camper Spare Parts List to Carry While Camping

(They’re available here on eBay)

3. Check the 12V roof power cable is plugged in (and working)

Most Jayco camper trailers have a plug for the 12V roof power cable.

They are usually either the cigarette-lighter style 12V plug and socket…

…or a 2-pin plug:

During the roof windup the cables can get caught and the plug can get dislodged.

Also:

Because the cigarette-lighter style 12V socket is right next to the sink they’re prone to corrosion:

This is one of the reasons why sticking some 8 mm tubing over the tap is on this list: 35 Most Popular Jayco Camper Trailer Modifications

To easiest way to see if the socket is still working is to plug something else in and see if it’s getting 12V power.

If you DO have power at this plug, then it’s a problem ABOVE the sink in the roof light wiring assembly (skip to Step 5).

If it’s NOT working, then it’s a problem BELOW the sink somewhere between the charger and the socket.

But before you get excited and take the plug apart to inspect the connections…

4. Check the fuse and Setec connection

If no power is getting to the socket that supplies 12V to the roof then it’s likely there’s a blown fuse.

Which fuse is it?

Unfortunately they’re all wired differently. You’ll need to pull them out one at a time and see which one is blown

(they’re see through)

If the fuses are okay then check the blade connecters that go into your Setec charger

Try giving it a wiggle… and if it still doesn’t work then plug the lights’ connector into another input on the Setec that you know that does work (to eliminate a circuit fault on the Setec)

If there’s power from the charger but still no power to the 12V socket by the sink?

Then it’s likely the socket is kaput.

5. Check that the light globes haven’t all blown (at the same time?!)

Blown globes aren’t the usual culprits for lights not working in a Jayco camper trailer

(and it would be pretty rare for all of them to go at the same time)

But, by now you’ve confirmed:

• You have 12V power supply
• The roof power cable is plugged in and working
• The metal lever on the roof safety kill switch hasn’t failed to drop

So although this is highly unlikely, I’ve put this step here because it’s a quick check:

If you replace just one bulb you’ll know if that’s the problem.

Still not working?

6. Test the continuity of the roof wiring

If you’ve made it this far and your lights are still not working then things are getting a little trickier.

The most likely culprit to cause a break in the circuit is a fault in the roof safety switch

(it’s the obvious spot to check first because there’s connectors that can come loose AND moving parts that can break)

Turn off the battery isolation switch, unscrew the roof safety switch, and join the wires back together.

If you now have lights then we’ve found the problem…

…if not then it’s time to get someone who knows their way around a multimeter to look for a break in the wiring

This next section is for those that DON’T have 12V power to other parts of their camper…

7. Make sure the battery isolation switch isn’t turned off

Lights run off the 12V circuit regardless of whether you’re plugged into 240V power or not.

A lot of Jayco camper trailers have a battery isolation switch to cut-off the 12V circuit from the battery

(this stops 12 V appliances draining the battery when the camper isn’t being used)

The problem is that this switch isn’t always labelled…

…and sometimes people forget to check this (especially if it’s something that’s normally left on all of the time)

HINT: This might be the cause if your external light and stove igniter aren’t working either

8. Charge (or change) your battery

If the battery isolation switch is on… but there’s no power to the stove igniter, internal lights, or external lights?

Then it looks like you have a flat battery.

Try to plug the van into 240V. Hopefully the Setec power supply can charge the battery.

But, if the battery has gone too flat, the onboard charger may not bring it back up

(you’ll need to disconnect the battery and charge it using a smart charger)

Summary: Fixing lights not working in your Jayco camper trailer

If you find your lights not working in your Jayco camper trailer then a simple fault-finding process will help you find the common causes.

To be honest though, 90% of the time it’s the roof kill safety switch

(which is why getting rid of it is on the list of the 35 Most Popular Jayco Camper Trailer Modifications)

You might also like this article: 23 Tips For New Jayco Camper Trailer Owners