Trailer Wiring Weirdness
Fleet Owner
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From: Easton,Ks
The PCM (EEC) Power relay supplies power to the coil of the Fuel pump Relay, all Fuel Injectors, running power to the PCM Computer, the Transmission solenoids, IAC valve, EVR solenoid, AIRB solenoid, AIRD solenoid and the canister purge solenoid. All of these are powered by the red #361 wire.
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mine does same its because the signal to apply the trailer brakes used by the control box is the brake light switch. this wire also activates the brake lamps of course, the reason is the 4 ways flash the brake lights so you are getting a flashing 12 volt activation signal to the box.Turn the gain or sensitivity way down when using 4 ways. or dont use them while driving.
Fleet Owner
Joined: Aug 2005
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From: Easton,Ks
mine does same its because the signal to apply the trailer brakes used by the control box is the brake light switch. this wire also activates the brake lamps of course, the reason is the 4 ways flash the brake lights so you are getting a flashing 12 volt activation signal to the box.Turn the gain or sensitivity way down when using 4 ways. or dont use them while driving.
When the hazard switch is pushed (up) it disconnects the BOO circuit from the tail lamps. That way no power will go to the controller.
You have hooked the controller to the wrong wire.
You have the controller hooked to wire #2 or #3 and it should be hooked to #511.
Fleet Owner
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From: Easton,Ks
The BOO circuit is the Brake On and Off circuit that runs from the brake pedal Brake On and Off switch to the Multi-function Switch by way of the Hazard switch. It is circuit #511, a light green wire.
Attachment 282123
Attachment 287797
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Attachment 282123
Attachment 287797
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Fleet Owner
Joined: Aug 2005
Posts: 23,667
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From: Easton,Ks
The brake controller is drawing power from one of the red #361 wires instead of fuse "T".
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Sounds like the back-up lamp wires are shorted to the side marker lamps.
Yes it was I used a screw that was too long.
Covered in post #19 above.
The multimeter shows zero ohms between 511 and control. and some resistance between 2 and 3 and the control.
The brake controller is drawing power from one of the red #361 wires instead of fuse "T".
Yes it was I used a screw that was too long.
Covered in post #19 above.
The multimeter shows zero ohms between 511 and control. and some resistance between 2 and 3 and the control.
The brake controller is drawing power from one of the red #361 wires instead of fuse "T".
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I posted the results last night and saw it at the bottom of this thread but it is not here now. So, here it is again.
This was done with the battery disconnected. Relay 1 being closed (energized) was simulated by using a jumper wire.
With flashers off (button down) 511 to 2 is 2.2 ohms. 511 to 3 was 1.2 ohms.
With flashers on (button up) all were 1.5K ohms.
The results were the same with the jumper in or out.
This was done with the battery disconnected. Relay 1 being closed (energized) was simulated by using a jumper wire.
With flashers off (button down) 511 to 2 is 2.2 ohms. 511 to 3 was 1.2 ohms.
With flashers on (button up) all were 1.5K ohms.
The results were the same with the jumper in or out.
Fleet Owner
Joined: Aug 2005
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From: Easton,Ks
When not braking does not the light being on just tell you that you have connection through the brake coils on the trailer.
Pressing the brake will turn the light on with the hazards on or off.
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Relay 1 is in the larger box. it is the one labeled PCM Power Relay on your photo in post 13. I call it that because the cover for the box uses 1-5 to ID the relays. It uses 1 through 24 for the fuses.
Don't know for sure as I never had a trailer on it. I always thought it just showed when current was going to the brakes. I can test it with a resistor if you think it is important.
With the key on or off, hazards off, the controller light turns on when the brake switch is activated.
With the key off, hazards on, the light does not turn on until the brake is pressed.
Key on, hazards on, controller light is on. Pull relay one, the light goes out until the brake is pressed then it turns on.
Don't know for sure as I never had a trailer on it. I always thought it just showed when current was going to the brakes. I can test it with a resistor if you think it is important.
With the key on or off, hazards off, the controller light turns on when the brake switch is activated.
With the key off, hazards on, the light does not turn on until the brake is pressed.
Key on, hazards on, controller light is on. Pull relay one, the light goes out until the brake is pressed then it turns on.