Brake Fuse Keeps Blowing with New Wiring Harness Installed

Question:

I have been blowing my brake fuse several times after converting to a seven pin. I have put an ohm meter to the harness side and there are no wires touching another and have checked to see if any of them are shorted to ground. Its a gmc factory harness on a 96 savanna, I unplugged the harness at the connection and quit blowing any fuses. While installing the new harness I noticed that the wires looked burnt even though they had never been used. Any suggestions, thanks

asked by: Mike

Expert Reply:

If you keep blowing a fuse and the wires on your new harness looked burnt then there is a good chance that the harness is your problem.

When a fuse keeps blowing like that it usually means there is a short somewhere. Check the connector on both your tow vehicle and your trailer to make sure they are clean and free of any rust, corrosion, or debris.

If the connectors look good then you will want to move on to troubleshooting the wiring on your tow vehicle and your trailer. Look for any places where the wiring is bent, corroded, exposed, or damaged (sounds like your harness). You can use 16 Gauge Wire # 16-1-1 for a single wire or the Bonded 4 Wire # 16-4B-1 for a full harness to replace any damaged wiring. Butt Connectors # DW05744-5 will help to complete the install.

If everything looks good aside from your new harness then I would definitely try replacing that first. Just because it hasn't been used doesn't mean it cannot be damaged.

expert reply by: Jon G