Right rear brake light not coming on.

[Domi]

We were getting ready to leave today and doing the rear light check and I found that the right rear break light would not come on. I looked at the bulb and it looked okay but we stopped and got replacements anyway. The replacement made no difference. I am guessing the break signal is not getting to that lamp, but where do I start looking?

To summerize, I have turn signal and running lights to the right rear just not break lights. I have all fuctions to the left rear. Looking at the bulb holder there are only two wires, a green and a black.

I am guessing I have a missing connection someplace between the hitch and the light but it would be great if someone could help me narrow down where to look.

Thanks,

John

 

[danemayer]

Re: Right rear break light not coming on.

I would start at the umbilical connection where the trailer plugs into the truck connector. Make sure contacts are clean on both sides. Also, it's possible to bend the connectors a little on removal of the plug, weakening the connection. With brakes ON, and someone watching the trailer lights, wiggle the connector. If the brake lights come on, it's a weak connection.

 

[Jesstruckn/Jesstalkn]

Re: Right rear break light not coming on.

This might help.

 

[ram_1955]

Re: Right rear break light not coming on.

To summerize, I have turn signal and running lights to the right rear just not break lights. I have all fuctions to the left rear. Looking at the bulb holder there are only two wires, a green and a black.

Does your trailer have red or yellow turn signals? If it has red the element that is the turn signal is also the brake element. If it is red I would be looking at the truck for a problem. Use a test light at the truck using the diagram posted by jesstalkn. At 5 & 6 you should have solid light when brakes are applied. Remember in troubleshooting to divide and conquer. Testing at the truck connection will let you know weither it is a truck issue or trailer issue.

 

[rhodies1]

Re: Right rear break light not coming on.

Check your vehicle manual to see if your tow vehicle has separate fuses for the right and left brake lights .l have seen this on a few vehicles.Also it seems strange to only have 2 wires going back to your lights usually you have a white for ground,brown for tail lights and depending on the installer a third coloured wire for signal/ brake lights.Check to see how many wires are running to the left side of your trailer.

 

[gasman]

If your tow vehicle has a common brake and turn light, it will have a diode in the wiring that sends the brake signal only to the rear turn circuit. If that fails, the turn signal will work but not the brake light. If your TV has separate brake and turn lights, you may have a signal combiner problem.

 

[Domi]

Update on the issue:

This morning I found that the break light on the right side of the truck had blown out. Replaced the break light and still had the issue. I checked the fuses and the looked and measured good. I looked at the voltage on the connector and pin 6 to ground with the breakes on is 0.06V (left side is 11.59V). When the turn signal is on the voltage changes as I would expect.

The truck has separate turn signals and break lights, they are on two separate bulbs. Thinking it might be a combiner issues as Gassman mentioned. Is this something easy for me to get at or do we need to take the truck in?

Thanks for all the great help. It is so great to get this kind of help when needed.

John

 

[fin72fan]

I have the same problem on a new 2016 Hartland Gateway 3400SE. All the lights functioned correctly on the 2005 Hartland Landmark we traded in. when we brought the new coach home and I was backing it in the driveway my wife alerted me to the fact that all the light were working except for the left rear break light. Will try these suggestions out and see what happens. Thanks to jesstalkn for the wiring diagram.

 

[Jesstruckn/Jesstalkn]

On El Chucko's brand new 2016 Big Horn he had a brake light not working. We pulled the in-op tail out and found all of the little pinch connectors were not pinched all the way in. I took a pair of pliers and pinched them all the way in. Everything worked good after that.

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[rxbristol]

There should be a separate straight line type plug that all the vehicle wires to into and then the wires go to the trailer plug--check to make sure the brake wire is good there.

 

[Jesstruckn/Jesstalkn]

Update on the issue:

This morning I found that the break light on the right side of the truck had blown out. Replaced the break light and still had the issue. I checked the fuses and the looked and measured good. I looked at the voltage on the connector and pin 6 to ground with the breakes on is 0.06V (left side is 11.59V). When the turn signal is on the voltage changes as I would expect.

The truck has separate turn signals and break lights, they are on two separate bulbs. Thinking it might be a combiner issues as Gassman mentioned. Is this something easy for me to get at or do we need to take the truck in?

Thanks for all the great help. It is so great to get this kind of help when needed.

John

The 6 volts sounds more like your on the brake controller post
Are checking the right and the left post ?



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[Domi]

Quick Update:

Had the truck into the dealer this week. It is a modual (I am guessing the combiner mentioned above) that is not working. New one on order. I will put up a final post once we know for sure it works and if there is a non dealer fix for this.

Thanks for all the help,

John

 

[Bob&Patty]

What module was ordered?? Was it the taillight bulb plate that screws to the light assembly? They were known to melt at the contacts. I would coat all the bulb contacts with dialectric grease when you install them. My question is.....how is your TV wired....does your TV have seperate fuses for the trailer and truck lights? IF so then the brake lights on the trailer have nothing to do with the TV. Just asking.

 

[Domi]

What module was ordered?? Was it the taillight bulb plate that screws to the light assembly? They were known to melt at the contacts. I would coat all the bulb contacts with dialectric grease when you install them. My question is.....how is your TV wired....does your TV have seperate fuses for the trailer and truck lights? IF so then the brake lights on the trailer have nothing to do with the TV. Just asking.

Bob,

They are say that it is the whole fuse block up by the driver side dash. That is where all the fuses are for the trailer lights are located. I assume that is where the combine the running, turn and brake lights together and send them to the trailer as they are all on one wire from the back of the truck through the pig tail to the trailer. The right break light indication does not show up at the pig tail.

The Trailer Stop and Turn trailer fuse is a different fuse then the truck (the truck has a stop and the right and left turn fuses). The Right Trailer fuse does both Stop and Turn so I an guessing that is where the combine them. I looked at both sides of the use block and did not see any broken wires although I will bring home an inspection mirror tomorrow and check it again. That is about the only thing other than an internal break that I can see causing.

We will know on Wednesday and will make sure that it works once they replace the whole thing. I know that a fuse is not bad as I looked and measured them when I was troubleshooting the issue a week ago.

Thanks for the input. Hopefully they will have got it right.

John

 

[Bob&Patty]

John, I hope they are correct also. SO, was it a melted wire or an internal connection problem. Just so I know....is it the junction box on the inside of the firewall to left of the brake pedal?? Never seen one go bad in all the years on worked on Chevy/GMC trucks. Did someone have it out for anything. If so maybe they bent a contact causing a loose or bad connection. Just seems odd to me it went bad.

John, send me a PM with your PH# before you install it. Better yet, here is my PH#.........951-295-0168.

 

[Domi]

Re: Right rear brake light not coming on. SOLVED

Took the truck in today and it was the fuse block by the drivers door. Turns out there is a "Trailering modual" attached to the back of the block. That is what went out but it is physically part of the block so you have to order the whole thing.

There are separate fuses for the truck and trailer lights, either in this fuse block or the one under the hood.

Both brake lights work now and the right one is much brighter so I am pretty sure there was something in the block that was wrong since we got the trailer a year ago it just took a while to fail.

Thanks for all the help. Pictures are attached.

John