derekwilliams345
New member
EDIT SOLVED: Problem was Auto-Off feature located behind instrument cluster. Jumped pin 5 to pin 1 on c27 harness to bypass auto off feature.
Recently bought #4 and slowly going through the vehicle getting rid of rust and making things right.
1999 4runner Limited w/o DRL and w/fogs
My headlights stopped working recently when operated from the stalk switch. The parking lights will come on but the headlights will not. The high beams will come on when i pull the lever to "flash" them but not when i push the lever forward for normal high beam operation.
I know the bulbs are good because I've been jumping the HEAD relay in order to drive at night and also i can "flash" the high beams on.
I have checked/tested/replaced all relays and fuses. I have a complete parts truck (#3) i can steal parts from. It has a different Body ECU though...
I have a complete extra headlight stalk/switch i have tried so its not the switch.
HERE IS MY PROBLEM: On the coil side of my HEAD relay i have 12v and 0v with lights off. When i turn the lights on from the headlight stalk switch, i have 12v and 8v at the coil!!
So somehow, 8v is back feeding to the coil on the HEAD relay. From what i understand, instead of getting the additional 8v I should be getting continuity to ground once the lights are switched on. Ive checked both continuity to ground and voltage (8v) and i seem to have both on that side of the coil.
So i started tracing that 8v back to the Body ECU (red wire). I then started unplugging harnesses (there's 12...) until i lost the 8v. The harness that i unplugged which made the 8v go away had two incoming 12v wires. Black w/orange (goes to defog relay under hood) and Blue w/yellow (goes to DOME fuse under hood). I unplugged the defog relay, still had 8v. I unplugged DOME fuse and Boom, 8v goes away. But... without the DOME fuse, there is a lot of stuff that doesn't work!
WHERE IM AT NOW: The DOME circuit feeds 12v into the Body ECU and somehow 8v leeches through to the red wire which leaves the Body ECU and goes to the coil of my HEAD relay.
Does anyone know how the AUTO-OFF FEATURE works or have a diagram of the DOME circuit?! Once the ignition is off and the driver door is open it will automatically shut off the headlights. This will also trigger the DOME lights to come on so i assume they work together.
I traced the wires around the best i could and even took apart the Body ECU and cleaned up a little corrosion inside. My best guess is that the circuit board in the Body ECU has some components that got fried somehow. Im going to the junkyard tomorrow to hopefully find a new Body ECU to test. Considering im getting a consistent 8v leeching i would assume the problem is a resistor or relay and not a compromised wire somewhere in the vehicle.
Any suggestions or insight would be amazing, i know there are a few guys on here who have a lot of in depth experience with these trucks. Hope you guys see this!
[MENTION=10169]TheDurk[/MENTION]
[MENTION=81700]OrangeTexan[/MENTION]
[MENTION=139000]phattyduck[/MENTION]
EDIT: It looks like the Body ECU/ Junction Box is reasonably priced so i will try to find one in the junkyard tomorrow or buy one online.
Recently bought #4 and slowly going through the vehicle getting rid of rust and making things right.
1999 4runner Limited w/o DRL and w/fogs
My headlights stopped working recently when operated from the stalk switch. The parking lights will come on but the headlights will not. The high beams will come on when i pull the lever to "flash" them but not when i push the lever forward for normal high beam operation.
I know the bulbs are good because I've been jumping the HEAD relay in order to drive at night and also i can "flash" the high beams on.
I have checked/tested/replaced all relays and fuses. I have a complete parts truck (#3) i can steal parts from. It has a different Body ECU though...
I have a complete extra headlight stalk/switch i have tried so its not the switch.
HERE IS MY PROBLEM: On the coil side of my HEAD relay i have 12v and 0v with lights off. When i turn the lights on from the headlight stalk switch, i have 12v and 8v at the coil!!
So somehow, 8v is back feeding to the coil on the HEAD relay. From what i understand, instead of getting the additional 8v I should be getting continuity to ground once the lights are switched on. Ive checked both continuity to ground and voltage (8v) and i seem to have both on that side of the coil.
So i started tracing that 8v back to the Body ECU (red wire). I then started unplugging harnesses (there's 12...) until i lost the 8v. The harness that i unplugged which made the 8v go away had two incoming 12v wires. Black w/orange (goes to defog relay under hood) and Blue w/yellow (goes to DOME fuse under hood). I unplugged the defog relay, still had 8v. I unplugged DOME fuse and Boom, 8v goes away. But... without the DOME fuse, there is a lot of stuff that doesn't work!
WHERE IM AT NOW: The DOME circuit feeds 12v into the Body ECU and somehow 8v leeches through to the red wire which leaves the Body ECU and goes to the coil of my HEAD relay.
Does anyone know how the AUTO-OFF FEATURE works or have a diagram of the DOME circuit?! Once the ignition is off and the driver door is open it will automatically shut off the headlights. This will also trigger the DOME lights to come on so i assume they work together.
I traced the wires around the best i could and even took apart the Body ECU and cleaned up a little corrosion inside. My best guess is that the circuit board in the Body ECU has some components that got fried somehow. Im going to the junkyard tomorrow to hopefully find a new Body ECU to test. Considering im getting a consistent 8v leeching i would assume the problem is a resistor or relay and not a compromised wire somewhere in the vehicle.
Any suggestions or insight would be amazing, i know there are a few guys on here who have a lot of in depth experience with these trucks. Hope you guys see this!
[MENTION=10169]TheDurk[/MENTION]
[MENTION=81700]OrangeTexan[/MENTION]
[MENTION=139000]phattyduck[/MENTION]
EDIT: It looks like the Body ECU/ Junction Box is reasonably priced so i will try to find one in the junkyard tomorrow or buy one online.
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