Brake light issue, stumped.

Don't know about motorhomes, but in a standard vehicle, the Cyclops must be wired on a separate source, so if your regular brake lights fail the 3rd will still work. That is where I would start my problem solving, looking for a wire from the brake switch that does not activate the regular brake lights.

Trace the wire back to where it is connected to the main brake lights. You should find your problem pretty fast. I suspect itis where it is spliced into the main brake light circuit.

I had a similar problem this spring. I parked my coach outside for the winter and a squirrel decided to make the rear cap his winter home.. Check the wires for chewing by rodents. Or you may have a break. The problem is in the power wire between the main rear brake lights and the 3rd light..

At lot of RVs turn the center brake light on when the engine brake is activated. Your problem could be caused by the switching relay or whatever type of switch device CC uses to turn on the CBL with EB activation or add it back to the brake light switch circuit.
Randy

Hey SML,
Well Sir, this is something should happen to me. I have "Weird" issues more than most. Anyway, I think most of the answers you've received so far are good. I don't know if you read my thread on my wiring issue we had while on vacation. It was the J-1939 Data link that went south and killed ALL of my gauges, exhaust brake and cruise control. Well, extra long story short, it was a broken wire.

And, where was the break? Well, without a doubt, we, my son and I got seriously lucky in finding it. It was a bad crimp, on a pin, inside a Deutsch connector, that was rigidly mounted to a support bracket, above the air dryer.

Now, what does all this mean to you? While about 95% of the electrical problems on 95% of the autos/trucks/RVs/submarines/space ships etc. have lead to a bad ground, some are other problems. And, it is possible, that you may have a "broken" wire, just inside a connector some place along the line from the original connector to the brake light switch, exhaust brake link, or where ever it originates from. Hopefully it's going to be simple to repair.

"Tracing" a wire in these beasts is way easier said than done. Surely let us know what you find out.
Scott

FIRE UP wrote:
Hey SML,
Well Sir, this is something should happen to me. I have "Weird" issues more than most. Anyway, I think most of the answers you've received so far are good. I don't know if you read my thread on my wiring issue we had while on vacation. It was the J-1939 Data link that went south and killed ALL of my gauges, exhaust brake and cruise control. Well, extra long story short, it was a broken wire.

And, where was the break? Well, without a doubt, we, my son and I got seriously lucky in finding it. It was a bad crimp, on a pin, inside a Deutsch connector, that was rigidly mounted to a support bracket, above the air dryer.

Now, what does all this mean to you? While about 95% of the electrical problems on 95% of the autos/trucks/RVs/submarines/space ships etc. have lead to a bad ground, some are other problems. And, it is possible, that you may have a "broken" wire, just inside a connector some place along the line from the original connector to the brake light switch, exhaust brake link, or where ever it originates from. Hopefully it's going to be simple to repair.

"Tracing" a wire in these beasts is way easier said than done. Surely let us know what you find out.
Scott

Scott, I just spoke to tech support at Country Coach and they advise there is only one brake light circuit and the center light is normally fed from the driver's side tail light assembly or both tail lights for redundancy. Since both the brake lights work in the tail lights, that reduces the possibility that I have a broken wire/bad connection coming from the front of the coach. My issue must be in the back and I need to do more investigation. My observations yesterday indicate the wiring is good but there is obviously something I have yet to discover.

I did have my coach into the local Cummins/Onan shop for a full chassis service recently but they had no tasks inside the engine bay other than replacing the serpentine belt and filling the tranny with Transynd as part of the tranny service.

My back up plan is to isolate a brake signal wire at one of the tail lights, tap into it and run a new wire to the high mount light.

smlranger wrote:

FIRE UP wrote:
Hey SML,
Well Sir, this is something should happen to me. I have "Weird" issues more than most. Anyway, I think most of the answers you've received so far are good. I don't know if you read my thread on my wiring issue we had while on vacation. It was the J-1939 Data link that went south and killed ALL of my gauges, exhaust brake and cruise control. Well, extra long story short, it was a broken wire.

And, where was the break? Well, without a doubt, we, my son and I got seriously lucky in finding it. It was a bad crimp, on a pin, inside a Deutsch connector, that was rigidly mounted to a support bracket, above the air dryer.

Now, what does all this mean to you? While about 95% of the electrical problems on 95% of the autos/trucks/RVs/submarines/space ships etc. have lead to a bad ground, some are other problems. And, it is possible, that you may have a "broken" wire, just inside a connector some place along the line from the original connector to the brake light switch, exhaust brake link, or where ever it originates from. Hopefully it's going to be simple to repair.

"Tracing" a wire in these beasts is way easier said than done. Surely let us know what you find out.
Scott

Scott, I just spoke to tech support at Country Coach and they advise there is only one brake light circuit and the center light is normally fed from the driver's side tail light assembly or both tail lights for redundancy. Since both the brake lights work in the tail lights, that reduces the possibility that I have a broken wire/bad connection coming from the front of the coach. My issue must be in the back and I need to do more investigation. My observations yesterday indicate the wiring is good but there is obviously something I have yet to discover.

I did have my coach into the local Cummins/Onan shop for a full chassis service recently but they had no tasks inside the engine bay other than replacing the serpentine belt and filling the tranny with Transynd as part of the tranny service.

My back up plan is to isolate a brake signal wire at one of the tail lights, tap into it and run a new wire to the high mount light.

Well Sir,
You've definitely covered all the bases. This gets interesting. The run from either of the tail lights to the High mount third brake light is relatively short. So, the problem, should not be too, too difficult to locate, yeah sure. Easier said than done in most cases. Sometimes it's pretty hard to get at some of that stuff in the rear cap.
Now, this is assuming that CC is correct in their explanation of the third brake light wiring. We "assume" that it is. And, this is of course, assuming on my part that, obviously, you have "amber" turn signal lenses, correct? Now, if you do and, as you say "both" brake lights are lighting up correctly, well, then this will interesting. It is of course, possible that the LED might have gone south for the Winter. Keep us informed Sir, so I can be prepared when mine quits.
Scott

To add to what fireup said...

If you only have a single bulb filament that acts as both turn and brake lights, then a diode block is needed so the cyclops only turns on with the brakelights and never with either turn signal. Problem could be there.

Back to my previous post. If you have an LED 3rd brake light it most likely is illuminated when the engine brake is on. LED assemblies do not heat up and burn out like conventional bulbs when on for a long period of time. Ask CC if they turn the 3rd brake light on with the engine brake and work from there. A quick check is to turn the EB on and see if the 3rd BL illuminates. If it does the switching relay to turn it back in to a conventional brake light is bad or not seeing the appropriate switching signal.
Randy

FIRE UP wrote:

smlranger wrote:

FIRE UP wrote:
Hey SML,
Well Sir, this is something should happen to me. I have "Weird" issues more than most. Anyway, I think most of the answers you've received so far are good. I don't know if you read my thread on my wiring issue we had while on vacation. It was the J-1939 Data link that went south and killed ALL of my gauges, exhaust brake and cruise control. Well, extra long story short, it was a broken wire.

And, where was the break? Well, without a doubt, we, my son and I got seriously lucky in finding it. It was a bad crimp, on a pin, inside a Deutsch connector, that was rigidly mounted to a support bracket, above the air dryer.

Now, what does all this mean to you? While about 95% of the electrical problems on 95% of the autos/trucks/RVs/submarines/space ships etc. have lead to a bad ground, some are other problems. And, it is possible, that you may have a "broken" wire, just inside a connector some place along the line from the original connector to the brake light switch, exhaust brake link, or where ever it originates from. Hopefully it's going to be simple to repair.

"Tracing" a wire in these beasts is way easier said than done. Surely let us know what you find out.
Scott

Scott, I just spoke to tech support at Country Coach and they advise there is only one brake light circuit and the center light is normally fed from the driver's side tail light assembly or both tail lights for redundancy. Since both the brake lights work in the tail lights, that reduces the possibility that I have a broken wire/bad connection coming from the front of the coach. My issue must be in the back and I need to do more investigation. My observations yesterday indicate the wiring is good but there is obviously something I have yet to discover.

I did have my coach into the local Cummins/Onan shop for a full chassis service recently but they had no tasks inside the engine bay other than replacing the serpentine belt and filling the tranny with Transynd as part of the tranny service.

My back up plan is to isolate a brake signal wire at one of the tail lights, tap into it and run a new wire to the high mount light.

Well Sir,
You've definitely covered all the bases. This gets interesting. The run from either of the tail lights to the High mount third brake light is relatively short. So, the problem, should not be too, too difficult to locate, yeah sure. Easier said than done in most cases. Sometimes it's pretty hard to get at some of that stuff in the rear cap.
Now, this is assuming that CC is correct in their explanation of the third brake light wiring. We "assume" that it is. And, this is of course, assuming on my part that, obviously, you have "amber" turn signal lenses, correct? Now, if you do and, as you say "both" brake lights are lighting up correctly, well, then this will interesting. It is of course, possible that the LED might have gone south for the Winter. Keep us informed Sir, so I can be prepared when mine quits.
Scott

Scott, this coach does not have amber turn signals. I specifically asked the tech guy at CC about any diodes that might be installed and he said there were none. I have been able to look at all the wiring at the rear cap (a real collection of wires, crimp connectors, etc) and I see nothing like the diodes I have seen and used. The LED high mount light works fine if you connect it directly to a 12v source. I tested it again tonite at the coach and it works fine.

As you know, I am on my learning curve with this new-to-me beast.