Electrical gremlin help

[waternutt]

Hope the electrical smart folks on here might help me out.

It appears that whenever I have my boat trailer hooked up I blow the fuse for the reverse lights in my truck. Never has any issues otherwise.

Any ideas on where to start? I would like to stop replacing fuses.

 

[Beachbummer]

Do you have a 5 pin trailer connector? One that uses the reverse signal to disengage the trailer brakes? Maybe the mechanism has a short or draws too much power?

 

[Dean P]

Check the wires. Something is grounding itself out.

 

[waternutt]

The trailer is wired with a 5 pin connector. I use a 5 pin to 7 pin adapter to connect to my truck. I wonder if i should just wire the trailer with a 7 pin connector.

 

[Beachbummer]

The issue is not the connector, but that the current draw on the reverse connector is way too high and blows the fuse. Do you have a multi-meter? I suspect the resistance of the reverse light cable to ground is way too low (Short) either the cable shielding has worn/broken and it touches the trailer chasis, or the electric mechanism itself that should stop the brakes from actuating is damaged drawing too much power. With a multi-meter set to Ohms, you can hunt this, by checking the trailer between the reverse cable and ground. Same check right at the reverse actuator/solenoid and it should tell you if it's the cable or the solenoid.

 

[waternutt]

I do not have a multi-meter but can get one from my neighbor. So the culprit will probably be the one with the lower resistance?

Thanks for the tip. I will check it out.

 

[Beachbummer]

So to confirm the issue check the cable first, If it shows zero resistance you know you have a short... if it shows a lot of resistance it may be an intermittent issue, you can shake the wiring and watch the resistance. The next step is to get closer to the solenoid and test. if the solenoid shows higher resistance then it's the cable. If the coil shows very little resistance, the coil is bad. You could disconnect it for now and use your manual lockout for reversing until you get it fixed if its the solenoid.

Best of Luck