bruno
NAXJA Forum User
- Location
- Los Angeles
1996 Jeep Cherokee 4.0 5spd 4x4 96k miles.
Electrical Problem; I suspect bad Headlight Switch....Help!!
During daytime driving (headlight switch off position) no issues of any kind, car is perfect, all functions and accessories perfect.
During nightime driving (or when headlight switch is on in either park or headlight on mode), after 5-10 minutes, pressing brake pedal results in Hight Mount (3rd) brake light and both tail lights stuck in the "brakes on mode". Pressing the pedal results in these brake lights gives a little more brightness to them, so you can tell that the brakes are applied...but the lights are already lit fully by then. Releasing the brake pedal results in these 3 tail lights stuck on.
When this occurs, I have done the following things, and brake lights are still stuck ON:
Disconnected brake pedal switch
Removed illumination relays
Removed hazard flasher relay
removed door/light/key in buzzer relay
Removed power and fuses from car alarm
Removed trailer light harness completely from vehicle.
The three brake lights remain stuck ON.
I then turn headlamp switch to off position. All lights turn OFF. If I now press the brake pedal, the tail brake lights (all 3) come on, and the dash lights come on. I am able to adjust the brightness of the dash lights with the dimmer when this occurs. The illumination relay under the dash clicks, and I can feel it with my fingers. REMOVING the relay when this occurs still does not stop the brake light/dash light issue.
After a few minutes of everything being off, headlight switch in OFF position, pressing brake pedal only results in brake lights coming on when they should. Dash lights do not come on with brake pedal application. The illumination relay does not click.
When the problem occurs, I have also tried parking, turning everything off, and arming car alarm. The dash and marker lights flash (as they are supposed to), but the 3rd brake lamp also flashes too.
If I wait a few minutes and arm the alarm, only the dash and marker lights flash. No 3rd brake light.
I have inspected all wiring, and cannot find any shorts. All connectors are snug. No fuses are blown, and I have checked all fuses in dash, relays in dash, and high power fuses and relays under hood electrical compartment. The vehicle drives fine, everything works, and just passed California emissions even though it is a 49-state car.
I have traced the electrical schematic, and this one beguiles me-- I have viewed many internet posts, and at this time suspect the HEADLIGHT switch as the main culprit. It appears to have all connections tight and does not get hot to the touch. The problem only occurs after using the switch and pressing the brakes. If I just leave the switch on, the brake lights do not stay on, UNLESS I press the pedal. I could drive all night with normal lighting and turn signals. The high beam/low beam switch, and hazard flashers all work normally.
Just for kicks, I disocnnected the rear light harness when the problem occurs, and then ONLY the right brake light and 3rd brake light stay on. This is confusing, because in pulling the lighting harness in the back (where the trailer harness hooked in to-- this was a u-haul adaptor, you disconnected the regular factory harness connector, plugged in the u-haul trailer light connector adaptor, and plugged the other end of factory harness to the other end of the u-haul harness.
As to why the brake lights are on with the factory harness disconnected is a mystery to me. But to add: When I got the car from family 2 months ago, both 3rd brake lights bulbs were burned out. I replaced them both with the factory 922 bulbs, and those were what I removed that were burned out. To eliminate these lamps as issues, when the problem occurs, I have disconnected the 3rd brake light connector, but the dash lights up as usual when the brake pedal is pressed. After a few minutes, in the headlight switch OFF position, all is normal again.
Please advise. I apologize for the lenghty post. I would only hope that some other poor soul could benefit as I have from fully detailed posts.
Electrical Problem; I suspect bad Headlight Switch....Help!!
During daytime driving (headlight switch off position) no issues of any kind, car is perfect, all functions and accessories perfect.
During nightime driving (or when headlight switch is on in either park or headlight on mode), after 5-10 minutes, pressing brake pedal results in Hight Mount (3rd) brake light and both tail lights stuck in the "brakes on mode". Pressing the pedal results in these brake lights gives a little more brightness to them, so you can tell that the brakes are applied...but the lights are already lit fully by then. Releasing the brake pedal results in these 3 tail lights stuck on.
When this occurs, I have done the following things, and brake lights are still stuck ON:
Disconnected brake pedal switch
Removed illumination relays
Removed hazard flasher relay
removed door/light/key in buzzer relay
Removed power and fuses from car alarm
Removed trailer light harness completely from vehicle.
The three brake lights remain stuck ON.
I then turn headlamp switch to off position. All lights turn OFF. If I now press the brake pedal, the tail brake lights (all 3) come on, and the dash lights come on. I am able to adjust the brightness of the dash lights with the dimmer when this occurs. The illumination relay under the dash clicks, and I can feel it with my fingers. REMOVING the relay when this occurs still does not stop the brake light/dash light issue.
After a few minutes of everything being off, headlight switch in OFF position, pressing brake pedal only results in brake lights coming on when they should. Dash lights do not come on with brake pedal application. The illumination relay does not click.
When the problem occurs, I have also tried parking, turning everything off, and arming car alarm. The dash and marker lights flash (as they are supposed to), but the 3rd brake lamp also flashes too.
If I wait a few minutes and arm the alarm, only the dash and marker lights flash. No 3rd brake light.
I have inspected all wiring, and cannot find any shorts. All connectors are snug. No fuses are blown, and I have checked all fuses in dash, relays in dash, and high power fuses and relays under hood electrical compartment. The vehicle drives fine, everything works, and just passed California emissions even though it is a 49-state car.
I have traced the electrical schematic, and this one beguiles me-- I have viewed many internet posts, and at this time suspect the HEADLIGHT switch as the main culprit. It appears to have all connections tight and does not get hot to the touch. The problem only occurs after using the switch and pressing the brakes. If I just leave the switch on, the brake lights do not stay on, UNLESS I press the pedal. I could drive all night with normal lighting and turn signals. The high beam/low beam switch, and hazard flashers all work normally.
Just for kicks, I disocnnected the rear light harness when the problem occurs, and then ONLY the right brake light and 3rd brake light stay on. This is confusing, because in pulling the lighting harness in the back (where the trailer harness hooked in to-- this was a u-haul adaptor, you disconnected the regular factory harness connector, plugged in the u-haul trailer light connector adaptor, and plugged the other end of factory harness to the other end of the u-haul harness.
As to why the brake lights are on with the factory harness disconnected is a mystery to me. But to add: When I got the car from family 2 months ago, both 3rd brake lights bulbs were burned out. I replaced them both with the factory 922 bulbs, and those were what I removed that were burned out. To eliminate these lamps as issues, when the problem occurs, I have disconnected the 3rd brake light connector, but the dash lights up as usual when the brake pedal is pressed. After a few minutes, in the headlight switch OFF position, all is normal again.
Please advise. I apologize for the lenghty post. I would only hope that some other poor soul could benefit as I have from fully detailed posts.
