Brake light stays on, when all systems are off

[Ron, Debra & Foxy]

I bought a 2010 Diesel Solera Sprinter from FreightLiner used with 18K miles. Had a rear-camera, bluetooth, and AM/FM/CD installed. Everything working great. Winterized and discussed new water filter, upon setting up for camping again. All systems worked fine for a few days, then upon parking - the lift rear brake light, or bright tail light stayed on. Double-checked all systems and everything was shut down. What would cause this upon turning off the ignition? No coach power left on at all. Water heater turned off for winter. Took to a repair shop - and they traced everything after taking coach apart - replaced the main module........ light still comes on and drains battery to the point can't start or even turn over.....
Can anybody shed some light on this?
Ron
Portland, OR
2010 Solera 24S
Freightliner Sprinter Chassis from Mercedes still under warranty.

[donanddona]

I'm going to take a chance on this. During your exterior light check do all lights work properly. Running/parking lights, turn signals, brake lights, turn signals with brakes applies, emergency flasher, all lights? If so then I would look at the brake light switch. IT should be held in place by a metal clip. Look closely at the wires to see if someone has altered/tapped in to one of them, or is one frayed/cut? As an available constant hot some mechanics will tap the resource.

[limblips]

Not familiar with your particular model but do know something about brakes and lights. I would begin by looking to make sure your right brake light is not burned out (have someone put the brakes on while you watch). It seems to me that you may have an issue with the brake light switch. I have seen it before where the switch fails internally and provides continuity. Most brake lights work even if the keys are out and the unit is not running so if the switch is failed it could be providing power to the lights.

[Ron, Debra & Foxy]

Thank you. It is only the right rear. Does each side (right and left) have it's own switch?

[Kaadk]

I'm not familiar with the MH, but does it have fog lights? Back when I used to travel in Europe a lot of their cars would turn on the left rear light at full power when the fog lights were on, to improve rear visibility.




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[donanddona]

Normally no. One brake switch powers both brake lights. The brake switch is mounted under the dash frame. About half way up the brake pedal. Normally depressed by releasing the brake pedal, the pedal comes in contact with the frame mounted switch, pushing in a button, turning off power to the rear lights. Depressing the brake pedal releases this button sends power to the lights. But wait.... First we must validate "ALL" modes of operation to these rear lights. This will help narrow possibilities (like emergency flashers). Not to mention shorts in wiring. Please validate first!

[limblips]

Ditto the above. Only one switch but your 4 ways are hot without the key on. If your 4 way flasher unit were bad internally it could be your problem. I would now go and pull the flasher to see if your light goes out. If it involves a short to hot somewhere, troubleshooting will have to start by pulling fuses until the light goes out to find the errant circuit.

[iceblaze580]

Let me ask do you happen to have a break controller installed I had one go bad on my truck and it would keep the break lights on

[Ron, Debra & Foxy]

Nope. No brake controller. Neve towed.

[Flybob]

Turn on your four ways and see if they work. If a bulb is burned out, and they use a mechanical flasher, they may not draw enough current to make it flash., Hence one light on and other out ( burned out).

[Mojojojo]

If the turn signals use the same bulb it's possible there is a problem with the switch for that hence only one comes on

[ChibullsAN]

My wife's car had its brake lights stay on but that was the switch for the brake pedal. It's always set to on unless the pedal is all the way up. If that switch gets loose it will light up the brake lights. Not that this is your problem, but another place to look. The only other way is to find the wires for that bulb and work backwards until you find the power source.

[Taranwanderer]

The fact that only one brake light is coming on leads me to believe it's not the brake light switch. Since it's a Sprinter chassis, you might have the "euro" package with the rear fog light (as has been suggested.) Maybe take a look at that switch.

[B and B]

Being a sprinter of European design is it possible there is a parking light switch turned on somewhere. I know some VW and Mercedes have a switch that turns the left rear light on when parking on the road to prevent a accident when parked.

[ChibullsAN]

Originally Posted by Taranwanderer

The fact that only one brake light is coming on leads me to believe it's not the brake light switch. Since it's a Sprinter chassis, you might have the "euro" package with the rear fog light (as has been suggested.) Maybe take a look at that switch.

Yeah you are right and I agree with you. But just another point to check I guess. Like I said though, start at the brake light and work forward until you can find the source of the voltage. It won't be spliced very often so it'll be under the dash somewhere most likely if it isn't a fog lite switch.