Help with a brakelight problem

[DEERE6030]

I need help on why my brake lights wont light up when the brake pedal is pressed; I checked all the fuses and relays their good, I checked the bulbs their good, I put in a new brake switch, The brake lights will illuminate when u turn on the headlights but when u press the brake pedal they don't get bright, even with the headlights off...suggestions please

 

[robertoa1a]

There is a trailer lighting plug somewhere tucked behind the rear bumper that can get shorted.

 

[DEERE6030]

ya i found that and pulled it out that's not it.

 

[2000StreetRod]

All brake lights?

I don't have a 1999 wiring diagram but I do have wiring diagrams for 1996 and 2000. There shouldn't be too much difference so I'll try to help.

You said your brake lights come on with the headlights but not when depressing the brake pedal. Are you sure it's not just the tail lights? Do both the tail brake lights and the high mounted stop lamp assembly (third brake light) illuminate with the headlights?

Power for all three brake lights comes from fuse 13 (15 or 20 amps depending on year) in the interior fuse panel. From there it goes to the brake pedal position switch. The power from the pedal switch is joined with power from the turn/hazard switch and then goes to the rear of the vehicle and then splits. One line goes to the third brake light. One line goes to the right brake light. One line goes to the left brake light. Each light has a separate ground.

If there was a short on the 12 volt side of any of the lights then fuse 13 would blow when you depress the brake pedal if it's functioning properly.

Do your brake lights illuminate when your hazard warning switch in ON? If so, then recheck fuse 13. If fuse 13 is good, then you'll have to trace the voltage as it progresses from front to rear. The brake switch could be installed incorrectly or there could be a broken connection or wire some where along the power path. You'll need a voltmeter or a 12 volt test lamp.

 

[DEERE6030]

all the lights work, but when the brake pedal is pressed the high brake light does not come on, and the other 2 brake lights don't get bright when the pedal is pressed.

 

[2000StreetRod]

Hazard lights OK

all the lights work, but when the brake pedal is pressed the high brake light does not come on, and the other 2 brake lights don't get bright when the pedal is pressed.

By "all the lights work" I'm assuming you mean when the Hazard warning switch is on. If so, then you'll have to trace the power path from fuse 13 to the lights with a voltmeter and probe to determine where you have an open connection. The first thing I would do is probe the input to the foot pedal switch. It should always be at 12 volts whether ignition if on or off. If it's not then check for voltage at fuse 13.

 

[Tavery1]

I've got the exterior lighting system diagrams from my haynes manual it says typical 95-99 but they should be pretty much the same. If you think this may be help PM me and I'll send you pictures(digi cam, my scanner doesn't work anymore) I leave for school in like 10 minuets and won't be home till 3 or so depends on if I do anything after.