Tail, marker & high beam not working

[Rick Rutel]

I have an unusual issue that I can not solve using standard diagnostics.  I have a 2008 Monaco Camelot 42pdq. None of the marker lights, tail lights or high beam will come on.  I have checked every fuse, switched out relays to make sure it wasn’t that, retested the fuses and each fuse and relay is good. Turn signals, brake lights are fine. Logically, it should be a fuse ir relay. It’s the combination of no high beam or marker lights that get me. My coach is not equipped with daytime running lights, but I jumped the relay and the high beams came in. No luck using the smart wheel either. Any ideas would be welcome. Dash and switch lights do work.

Edited April 15, 2022 by Rick Rutel
Missing information

[DavidL]

Wow, that is a nice clean dust free system.  How did that happen?

Anyway...beyond that its a crap shoot.  I would get a wiring schematic.  And check the grounds.

Determine if you are missing Plus or Minus with a Voltmeter.

Edited April 15, 2022 by DavidL

[ktloah]

If your fuses are all good, I would next look at the smart wheel box. My 04 Dynasty lost the headlights and turned out to be a burnt wire where it.plugs into smart wheel box..good luck

[BradHend]

Something up with your manual light switch perhaps?

[DavidL]

Any guess is a good guess.

Diagnostics requires test results.  Step 1 is "the light isn't turning on...is it missing Plus or Minus?"

Running around the rig looking at all the complicated stuff just detours around the problem.

You mentioned you did all the Basics.  Everyone has a different idea of what the Basics are.  But Ground or Supply IS the Basics.  Lets understand that first.

 

but the Flux Capacitor might be the problem.

 

Anyway, certainly the above is a little tongue in cheek...but lets get a baseline.  The fact you have different switched lights that are all not working points to a ground wire that is common between those separate circuits.

I am still impressed on how clean everything is.  A rig I would enjoy working on.  Most pictures are such rat boxes I hate even looking at the pics.

Edited April 15, 2022 by DavidL

[timaz996]

I'd go with what Ronnie said. Check your plugs on the VIP box. I had the same issue.

Tim

[Rick Rutel]

I have yet to do any work with the smart wheel. Where is the box located?

 

Never mind. I realized I already found it.  Hope it's not bad. They are on back order and cost close to $500.00

[ktloah]

Check all the connections  and clean any corrosion...good luck

[Tom Wallis]

A voltmeter is usually the best way to narrow it down. As you check any of these items see if they have voltage or not with the switches on. Find out where in the circuit you have power and where you don't and the problem is in between those points. Since the problem seems go to more than one circuit I would start right at the headlight switch and start working your way out. Also don't just check to see if fuses are good but check to see if they have voltage to them and through them.

Since you found the headlight relay and you know it doesn't have power, you've already narrowed the search area down. I'd head right to the headlight switch at this point.

[MyronTruex]

You could easily have two different problems not related. They just showed up at the same time. Happens all too often but starting at one of the running lights or tail lights that are not lit would be an easy place to get a reading.

A 12 volt test light is a great tool and won't fool you like a digital voltmeter can. Finding a ground for the test light can be problematic so I built a tool that is easy to use anywhere around the rv.

Using an extension cord and plugging something into the ground hole works but was cumbersome. A new empty three prong plug and some lamp wire and alligator clip made a long ground that can be run about anywhere. Just find an outlet nearby and plug it in. In the RV of course.

You can clip the alligator clip of the device to a 12 volt source and then clip your test light alligator clip onto the (ground) lug of the plug which will allow you to inject 12 volts but at an actual lower level. Using it this way your lights would come on at the same time but lower brightness as would the tester light be lower.

When you have the tester set up this way the test light will burn fully when you touch a ground and at a much lower light level when you touch the hot side of the light circuit for example. 

Without a schematic your symptoms do smell of a bad light switch. This is a common problem. 

When all else fails and you have no schematic a signal tracer can be used to work backwards from one of the effected lights. You connect the signal injector onto the marker light for example and then use a sniffer to chase wires. Of course this is impossible to follow the whole route but you can go to places where you would suspect a problem such as a fuse panel or a light switch.

 

[Rick Rutel]

OK. Found the issue.  Two to be exact. The light switch had corrosion on the contacts where the power to the markers go.  Electrical contact cleaner made short work of the corrosion and the marker lights came back on. As for the high beams, a loose wire at the base of the steering wheel and of all things, the high beam indicator light fell out of the socket, so no light.

Everything is now working correctly. Thanks for the assistance!

[ktloah]

That's awesome Rick, happy trails