Rear Running Lights blowing fuses.

[TX Bella]

I noticed that my rear running lights(daytime running lights and at night when the headlights are on) were not working. I replaced the fuse which continued to burn out. I checked the bulbs seemed fine. Removed the bulbs to see if there was a bad bulb socket, the fuse continues to burns out with no bulbs installed. The running head lights, marker lights, signals and brake lights work fine.

There must be a short somewhere nothing obvious I could find.

Any thoughts?

Thanks,

John

[DavidL]

Get a schematic, find out if there is a disconnect somewhere to isolate portions of the wiring harness.  Look at where the wires go into chassis holes to see if something got abrated and shorted.

Wiggle and check.   Wiggle other areas and check.

Basically you are going to have to isolate where the issue is and narrow in.

Edited March 6, 2022 by DavidL

[Larry Maida]

This is gonna sound weird but look at all exposed wires underneath. There has been a serge of rats chewing through wires especially if your coach was sitting along time. Also during these really cold nights if you are plugging in your block heater you are inviting then in and they like to chew wires. Just saying. 

[Dr4Film]

You have a positive wire that is shorted to ground somewhere, need to find the culprit.

[CorinthWest]

99 times out of 100, this turns out to be bad wiring on your trailer hitch.  Sometimes, like someone else said, it's hungry critters, other times it is caused by bottoming out the rear of the coach and pinching the wires against the receiver, and then other times is it simply shoddy workmanship or deteriorated wiring.  If this isn't it, I would start looking at the clearance lights for a pinched wire.

[cbr046]

Remove all the bulbs and put a light in place of the fuse.  When the light goes out you've found your short.  Better yet, use a low power noise source.  Wiggle wires and listen for breakups in the sound. 

- bob

 

[CorinthWest]

cbr046:  Good post.  Snap-On makes a neat tool for finding shorts too.  But definitely, when all else fails - start "wiggling".  LOL

[TX Bella]

Thanks for the input, The search begins.

[Mike H]

John,  Did you find the culprit?  I'm having the same exact problem.  All of my lights are working, including the upper clearance lights.  My side clearance lights and the rear running lights are out and I blow that 10amp fuse as soon as I try to use them.

[TX Bella]

I have the coach going to the shop next week to see if they can figure it out, will update you afterwards. 

I will be the first to admit I'm not electrically incline (outside of easy electrical I do most my maintenance). I'm thinking it's in the wiring harness somewhere. The shop said if they can't find it they might be able to wire the to the upper clearance lights? I guess the that wiring can handle the additional load?

Hoping they will find the problem and fix it correctly. I had a few repair shops say this is a chassis issue and didn't want to work on it.

[Mike H]

17 minutes ago, TX Bella said:

I have the coach going to the shop next week to see if they can figure it out, will update you afterwards. 

I will be the first to admit I'm not electrically incline (outside of easy electrical I do most my maintenance). I'm thinking it's in the wiring harness somewhere. The shop said if they can't find it they might be able to wire the to the upper clearance lights? I guess the that wiring can handle the additional load?

Hoping they will find the problem and fix it correctly. I had a few repair shops say this is a chassis issue and didn't want to work on it.

I may just have to do the same thing.  I'm in Florida and would be taking it up to Lazydays in Wildwood.  I just had it there having a slide Hyd issue repaired.  This is what I'm experiencing:

1.       4-Way flashers –OK

2.       Left turn signal – OK

3.       Right Turn signal – OK

4.       Head lights, Low Beam – OK

5.       Head lights, High Beam – OK

6.       Headlight Flash from steering wheel – OK

7.       Rear light flash from steering wheel – OK

8.       Upper run lights (front & back) – OK

9.       Brake lights/3^rd brake light – OK

10.   Driver console Switch lights – OK

11.   Driver console Switch light dim – OK 

12.   Dash warning lights – OK

13.   Tail Lights / Side running lights – NOT WORKING

I pulled the bulbs out of the tail lights (one was corroded but I cleaned it up) and both terminals showed a direct path to ground so I've got a short somewhere.  I have 12v to both of the fuse terminals but as soon as I insert a fuse and pull the headlight switch out the fuse blows.

[Dr4Film]

Once you find the direct short to ground and correct it, problem solved.

Start tracing wires to see if one might be chaffed and touching the frame.

[Tom Cherry]

Without beating the dead horse, I, as well as many, have the infamous “chafed” wiring issues.  Mine was a “spare” wire for a “generator or rear engine hatch” closure switch. OPPS. Monaco used the same main backbone cable on the Camelot as the Dynasty or maybe a carryover from the days when the Windsor and Camelot shared the same chassis.  I HAVE no switches.  But since Monaco ran the wire, it as connected to the “door/bin” alarm wire on my dash.  It was a GROUND signal.  I installed a fire protection system and slid over a bundle of wires, in the protective corrugated covers.  Opps….now a light and an alarm.  No help from Monaco, but I got the dash wiring print from Medallion, the vendor.  Right before I snipped the “never intended wire input” wire, I pushed and tugged and shifted the bundle.  Some 12 years later….it is still happy.  You can never tell where the chafed wire is….

Good Luck.

[Guest Ray Davis]

Is your toad connected?  If it is disconnect it & check again.  Check inside those toad connections a wire can pull out of its connection.

Edited September 12, 2022 by Ray Davis