brake and blinker fuses keep blowing out

1992 FORD F-150
130,000 MILES • 5.8L • V8 • 4WD • AUTOMATIC
Avatar
WEIRGOR
  • MEMBER
  • 1 POST
Truck was fine. I hoped in it this morning and I had no brake lights or not turn signals. I replaced the fuses to both the brakes and the blinkers but they blew out as soon as I put them in. I crawled underneath the truck back by the rear bumper and could find no short anywhere. This was only a visual check. What could be my problem?
Jan 29, 2015 at 2:41 AM
Advertisement
Avatar
CARADIODOC
  • ✓Experienced Mechanic
  • 34,413 POSTS
The trailer harness is still a good suspect, especially when multiple circuits are involved.

A simple trick to finding a short is to replace the blown fuse with a pair of spade terminals, then use small jumper wires to connect them to a 12 volt light bulb. A brake light bulb works well. When the circuit is live and the short is present, the bulb will be full brightness and hot so be sure it's not laying on the carpet or against a plastic door panel. Now you can unplug electrical connectors and move things around to see what makes the short go away. When it does, the bulb will get dim or go out.
Jan 29, 2015 at 2:45 AM
🔧 Tools & Auto Repair Parts
Find automotive tools, diagnostic equipment, and replacement parts for your next repair.
Shop on Amazon →
Paid affiliate link. As an Amazon Associate, we earn from qualifying purchases.
Add a reply
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.

Ask a new question

Frequently Asked Problems for This Vehicle