2002 Bulebird TC2000 brake lights blow fuse

[BigBlueBirdBus]

Hi all,

I have an issue I'm hoping I can get some help with.

I have a 2002 flat nose Bluebird TC2000 that I am having brake light problems with.

When I step on the brake pedal, the 15 amp fuse blows.

I have tried replacing the fuse, it blows instantly again when I step on the brake.

I took off the rear lights, they have a red and black wire going to them that dissappear inside the bus wall. I took the instrument panel off to check the wire going to the back of the fuse box, and all of the wires are black and go into a wire harness that dissapears further down into the dash. Which makes it difficult to trace the wires back to potential problem areas.

The top side of the pedal appears to have 0 wires going to it. The bottom side of the pedal appears to have only air (possibly some hydraulic) lines going to it but no wires that look like they go anywhere near the mechanism.

I know there should be a switch or something that tells the brake lights to come on... but I can't find it.

I have removed the swing arm, and flashy lights to pass the "it's not a school bus anymore" registration process. I capped the wires going to the lights on the top and bottom before tucking them back inside their holes.

If anyone can point me in the direction of where the switch would be located and/or why my fuse would be suddenly blowing for the brake lights now, it would be greatly appreciated.

Thank you!

 

[cadillackid]

the most likely thing that happens is that theres a short to ground either by the bulb or the socket..



most busses have 4 brake lights on the back.. (2 small 4" surface mount lights that are also license lights).. and the 2 red 7" combo lights that are stop / tail.. and then 2 orange turn signal only 7" lights.. (if texas bus those turn signals are red also). many modern busses have 4 tail lights as well.. they are combo with the brake lights.. one wire is the tail function.. (low filament) and the other is the Brake function (high filament).. ground is obtained from the body of the bus into the light fixture itself.. there may be a ground that has a ring around one of the screws.. so does the fuse blow when you have all 4 bulbs out of the red lights on the rear?



when you take the bulbs out do any of the sockets look corroded or nasty? usually water gets in at some point and kills the sockets.. sometimes cleaning helps but often i just replace the light..

 

[BigBlueBirdBus]

I took off the two lower lights to chase the wire colors. (The ones that have the license plate lights out the bottom) and one of the larger lights to see of they had the same color wires. (They did. Red and black)

The bulbs did look a bit worse for wear and the screws were rusted. I will pull the lights, clean up the connectors, and replace the bulbs.

Thanks for the quick reply. I will let you know if that's the issue.

 

[BigBlueBirdBus]

Update.

Pulled the light bulbs. With no pressure in the system, nothing happens. Fuse doesn't blow, no brake lights.

After pressure is built up, with no bulbs, fuse blows.

I thought maybe it could be the brake lights were so corroded that they were still causing a short with no bulbs in them. So I pulled them off, cut the wires going to all four brake lights and wire capped them all separately.

Stepped on the brakes. Fuse blew.

So. I think that means either the wires themselves are shorting out somewhere, or the switch is bad.

Where do I find the switch? There are no wires running to the pedal itself... on top in the cab, or under. Only air lines underneath.

I assume it's a pressure switch? It sees air pressure in the brake lines it lights up the bulbs? If I can find that I can just run new wires to new brake lights... but I need to know where/how the brake lights turn on.

Any help is appreciated, thanks.

 

[fo4imtippin]

I have a 2003 TC2000. Attached is the diagram from the manual. It says it is on the air brake pedal. You might have to cut apart the zip ties on the bundle going to it there is a whole mess of valves and wires in that area.

 

[BigBlueBirdBus]

Thank you for the diagram! Can I ask what you got that from?

The last time I was under the bus, it was air lines going to the side ports on the underside of the pedal where the diagram shows the switch. This should at minimum give me the lines I need to trace... or show me where I was overlooking the switch.

I can't get to the bus tonight, but I will look again as soon as possible and update.

Thanks again!

 

[cadillackid]

the fuse didnt blow with no pressure because pressure is what activates the brake lights. on my busses the brake switches are on the treadle valve at the foot pedal..


when there is no air pressure, pressing the pedal doesnt activate the switches

 

[Jstone-SKO]

Any luck with thiis? i have the exact same issue going on. Same bus. Im wondering if it is the abs morulator? There are some illuminated lights on this thing… i dont see any type wires or switch on pedal….it seems to actuvate electronically through that modulator…

 

[Spiritwalker]

I recently lost brake lights, flashers, turn signals and tail lights. Some modulator type thing in the wiring panel keeps clicking on and off and there's a light on that thing that follows on and off with the clicking sound. I've noticed a wire gets pretty hot when it's on then it clicks off and the wire cools down. Any ideas what I'm dealing with here? 1993 Blue Bird TC2000