Brake lights not working - Ultimate Advantage

sinatrablue · 07-15-2020, 03:17 PM

We have a 2000 Winnebago ultimate advantage, 38 foot. The brake lights have quit working. Hubby has changed out the Brake pedal pressure switches, checked all fuses and bulbs & looked for loose wires.. We have a five page wiring schematic from Freightliner but it does not show all of the wiring for this bus. All other lights work fine - just no brake lights.

Any suggestions or recommendations out there?

Morich · 07-15-2020, 03:57 PM

The most common cause of many light failures is corrosion on the bulbs or the bulbs themselves burn out. I would start out with checking the bulbs and then go part by part to test for voltage and ground at each pint along the line.
Did he check for voltage and ground at the bulb holders? Both sides are needed and looking for which is missing needs to be the first step as it can be as simple as a bulbholder not being grounded well.
I would expect the brake light wiring to be part of the chassis rather than the RV portion added by Winnebago, so a good check of those Freightliner plans would seem the next step as the two systems are separated coach and chassis.
Basic idea is that thing that a truck would have will work off the chassis battery and system, while things that are used for the RV are on the coach battery system. Ignore one while working on the other.
It is certainly a trek with limited info but can be done with time and effort.

sinatrablue · 07-15-2020, 04:10 PM

Howdy, neighbor! I see you are just down the road from us (Belton).

All bulbs have been checked
If you turn on the headlights, the still taillights work.
The tail lights & brake lights share the same bulbs.

Only the brake lights don’t work. That includes the two standard lights & the middle thin light.

He has gone through all of the schematics but unfortunately something is missing from what was sent by Freightliner. Freightliner claims this is all they have. hubby is a retired mechanical engineer with Shell Oil for 30+ years. He can fix anything but this has stumped him

I will forward your reply to him in the meantime. Maybe it will spark a new troubleshooting idea

Thanks very much for your quick reply

Morich · 07-15-2020, 05:32 PM

The tail lights & brake lights share the same bulbs.

Only the brake lights don’t work. That includes the two standard lights & the middle thin light.

This info has some good points to say that since lights are out in three places, we would like to think it was not bulbs. Not always true so may be worth a check as the alternate is tough going. A small point on the taillight and stop light is that it is likely to be a combo type bulb that has two filaments in one glass tube, so that one burning doesn't always mean the other is good, too. Often different set of wires to make each burn. Taillights are on all the time at night but the stop light comes on when braking?
But that is not helping if he has checked them.
Sorry can't be of more help but it gets back to getting the right info and that is pretty close to what he already knew!
One saving grace might be that it should not be a really complex route for the power to the bulbs as it has no reason to go into the RV/coach portion.
If I were looking at building the thing, I might go from the battery for starting the engine, to a fuse and then to the brake pedal as a switch and then just pretty straight to the back to connect to all three lights. One small point might be that I have seen the back lights installed so that taking the fixture off the coach, let's us pull a bit of wire out and maybe find where all three connect together. Just theory and not fact, but a loose connection at a joint of that sort would explain why all three are out at one time.
We would hope it was so easy, but not betting too heavy on that !!!

sinatrablue · 07-16-2020, 02:00 PM

Howdy again, neighbor.

Thank you again for your last reply yesterday. I've forwarded it to The Hubster in hopes that it might be helpful. Keep your fingers X'd and I'll certainly let you know if it works!

I really appreciate your time and help on this. Hope to be sending you good news soon ...

Renee (Belton, TX)

Indy Bob · 07-18-2020, 09:48 AM

Hope you find them culprit. My Ultimate Advantage has a similar problem. I push on the brakes and the yellow turn signal lamps light up. The tail lights work fine on the red covers. The turn signals work fine on the yellow. W I R I N G !!!!

sinatrablue · 07-20-2020, 12:23 PM

Hubby found the problem!!! It was a corroded wire in a huge bundle of other wires under the dash (see pix). This simple, tiny wire has caused a month's worth of agony!

Thank you to everyone who took the time help with this issue. It is very much appreciated. I sure hope we can pay this forward sometime.

Thanks again, everyone, and please stay safe out there.

Renee

sinatrablue · 07-20-2020, 12:24 PM

Hubby found the problem!!! It was a corroded wire in a huge bundle of other wires under the dash (see pix). This simple, tiny wire has caused a month's worth of agony!

Thank you to everyone who took the time help with this issue. It is very much appreciated. I sure hope we can pay this forward sometime.

Thanks again, everyone, and please stay safe out there.

Renee

Morich · 07-20-2020, 02:01 PM

That looks like a bear to find. Tell him you owe him a big one! That's the sort of thing that can take lots of tech hours to find, so for sure saved a bunch of money.

sinatrablue · 07-20-2020, 02:56 PM

Boy, you got that right, Morich!!! He can fix anything but this was pretty rough. We had an RV repair appt. for next Monday and just KNEW that was going to cost a fortune and probably not get done properly. Your suggestions / recommendations along with everyone else were a HUGE help. I cannot thank everyone enough for their time and help.

Safe travels to you and your family and thank you once more!

Renee

luce61906 · 09-29-2020, 04:23 PM

The bulbs can go in two different ways as the little knobs on the bulb are at different levels on the bulb. Anyway I had the same problem and like an idiot the bulbs were upside down.

Indy Bob · 10-22-2020, 08:20 PM

2000 Ultimate Advantage. Turn signals work fine. When I apply brakes the red upper lights come on. BUT..SO DO THE YELLOW TURN SIGNALS.
2 Red and 2 yellow when I brake.
Turn signals work fine on their own
Ideas where to start?

Bobn1957 · 03-13-2021, 08:46 PM

Sounds like you have a grounding issue if the turn signals and brake tail lights are sort of working.

Bobn1957 · 03-13-2021, 08:50 PM

The third brake light has a wire that comes from the front that is separate from the brake/turn signals, it's feed doesn't go through the multi-function switch.