Brake Lights Staying On

[Jackduncan]

When I unpluged the switch I lights were staying on that is what is confusing me where is it getting power. I open the switch and see that the contacts are working correctly but the light are staying on. The one thing I haven checked is where they spliced the wires in the engine compartment for the trailer connection. does anyone think I should cut all the wires and reconnect them? The power is coming from some where and I can't figure out where.

[l1v3fr33ord1]

Jack-

I recommend against exploratory surgery. It often causes more problems than it fixes.

[Jeep401]

Well the next most likely place for a problem is at the trailer plug or the converter box that should be right by the hitch. The box converts your two bulb stop and turn signal lights on the coach to a single bulb system that most trailer use. The box is a common problem, but normally won't turn lights on, not the other way around...

[Jeep401]

If the plug looks ok on inside, no corrosion where the wires are attached I would unhook the input side of the converter box and retest at the wires coming to that point.

[Jeep401]

The more I think about it, the box isn't probably going to be the problem, there is no power on it to short just sitting there, but there will be power in the plug that could be shorting across...

[c_oneil]

Just to be very clear you are telling us that even with the brake switch unplugged your brake lights are on. Could you check the input LEDs on your front Vansco and tell us what you see? The Vansco box is behind the plastic panel in front of the passenger's feet. There should be a paper chart taped to the back of the panel that lists all the LED assignments. The input LED for your "Service Brake" (on my '05 it is INPUT LED 24) should be off until you step on the brake and then it should be on. If the Service Brake input LED is lit then something is completing the brake switch circuit. Could be a short to ground on the wire going to your brake switch or someone has tapped into that circuit for some reason such as adding a trailer brake controller.

[Jackduncan]

I do thank you all for your help. I went back to the MH and when I turned on the key the lights were off again. I step on the petal and the lights work went on and off. After a few moments the lights stayed on again and would not shot off so I cut the trailer wires off and still the lights stayed on. I disconnected the switch on the petal and check to see if I had power at the switch on the white and black wires. What I found was that the white had the 12 v and the black had no power. I made the connect in the switch and when I did the 12V on the white read 0 until I let the contact go then the 12V were there again. This seem to be acting like a stuck relay. I there any relays that may be in the system? I know there is one by the master cylinder. What do you think?

[c_oneil]

No relay used to turn brake lights on unless your coach was modified. Relay near master cylinder powers hydroboost when no pressure from main pump (such as engine stopped). Front vansco sends signal to rear vansco and rear vansco powers brake lights.

[Jackduncan]

Question if I swap both the front with the back VMM2820 Vansco do you think that will correct the problem?

[Mcrosby]

Hi I’m jacks son in law,
-does anyone know where the feed to the brake lights come from? Blinker switch, ignition switch, strait from the battery...
-Should the brake lights work when the ignition is off like a regular vehicle? (They do not in this case.)
-the coach has a self resetting fuse panel and the #3 light indicates the brake lights. Does this fuse separate between the battery and switch or between the switch and the lights?
-does anyone have a wiring diagram for this coach?

[c_oneil]

My knowledge is primarily of my '05 model year and Jack's '04 could have some differences. They both use the Vansco mulitplexed electrical system for chassis electrical control. '04 was the first year it was used and there were some changes made after the first year. As for your questions:
-The power for the brake lights comes from the rear (in the battery bay) Vansco box.

-Ignition needs to be in the on position with engine running or not running for brake lights to operate.
-I don't know what you are looking at for a "self resetting fuse panel". If you are talking about the Vansco boxes (there are 2) they have 28 input LEDs and 20 output LEDs on the front. The output LED on my '05 is #12 on the rear box and the input LED from the service brake pedal switch is input LED #24 on the front box. The Vansco output circuits do have a breaker and self reset function from an over current event.
-I don't have a wiring diagram exactly. If you think talking directly by phone would help personal message or email me your number and a good time to call.

-

[Jackduncan]

If you can please call me tomorrow at 321-377-8072 around 12:00 to 2 and I will update you on what was done with no good results.

Thank You

[Mcrosby]

Yes Jacks MH has the vansco 88580 from what we can tell the rear unit runs the electrical in back of the bus and the front unit runs the front of the bus. The system in the front has the #4 that’s stays on and says brake sw and is lit as well as the brake lights. The rear unit I do believe it was the #11 that went to the brake lights is also on. We unplugged the switch at the brake pedal and there is no voltage on the black wire but there is 1 volt on the white wire (wire #52-A)
The harness in the very back of the bus that provides power to the brake lights is just 2 wires one black the other white (white wire #52-H) the white wire has 11 volts and the black wire has 0. I’m assuming the black is a ground. How does the circuit run? Battery to vansco to switch to light? Or battery to switch to Vansco to light? How is the brake switch at the pedal being completely removed and no power to the switch wires and the lights on possible? Is There something that powers the brake sw besides the vansco? Could it be getting the power from a blinker switch or the ignition switch? Could the vansco have failed causing a constant on? Sorry for all the question and thank you for all of your help in advance.

[DrDaveMA]

Swap the Vansco’s front to back and see if the brake led stays on.