'89 Electrical Short in Brake Wiring

I have tested all the wiring coming into the column and it all shows good voltage, with nothing lacking voltage. I thought I had a short in the column and went through all the wiring, replaced the blinker switch (it was broken), and now I'm basically back to square one. Using the column switch for the blinkers/ hazards blows the 15 AMP fuse. Using the brakes blows the fuse. I pulled the brake switch off and it no longer blows the fuse when using the brakes. I disconnected the blinker switch in the column and am running 2 custom wired switches for the blinkers. My custom switches run just fine, without blowing the fuse or the Relay.

I have checked voltage at the lights, and the plugs leading to the lights (on the wiring), everything seems okay back there. Bulbs are good, neither of them are blown. Blinkers/ Hazards work just fine as do the running lights.

Brake lights were also working intermittently when they didn't immediately blow the fuse out, but usually just the right side would work, not the left. Adjusting the column switch a tiny bit with the breaks applied produced results one time (left and right working), and again, the fuse blew out.

Any help, or advice on this issue would be appreciated. Or anyone with similar problems. Also, I am having trouble locating wiring diagrams for my particular year truck, or what I find preferable, a listing of the wires and their colors and what they go to.

I have tried another Bronco forum with poor results, and a not so helpful reply. I've ran through the forums here and it seems pretty nice, though I couldn't find anything for this particular issue.

1989 MARCH, Eddie Bauer 5.8L V8, 6" BDS Lift, 37x12.50 R15 Wrangler, American Eagle Mags

yo Murphy,

Welcome!

Here is a partial wiring diagram (same as by Ford) for your 89;

http://www.revbase.com/BBBMOTOR/Wd/DownloadPdf?id=21135

Fuse panel for Stop/Hazard R/W ckt 383

And;

http://content.chiltonsonline.com/content/images/8828/images/88286w24.pdf

If we can find more (and better) diagrams, then can disconnect a connector or more from along the path that ckt 383 follows to rear brakes and front & rear Hazards; thus isolating short area.

One common short area is the steering column support bracket at firewall where wiring pinches.

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Troubleshooting with a Test Light (low resistance) General; "...The other way I use a test light is to check for short circuits. This test is done by putting the test light in place of the fuse. I use the small Radio Shack jumpers to do this. If you turn off all of the lights or loads on the circuit being tested, the light will go out when you have found the short, but it will light brightly while the short is still there...." READ MORE

Source: by Chris B

Will look for more diagrams later.

Well, that test light for fuse idea never occurred to me, so I'm going to have to try that, and the wiring diagrams seem better than most stuff I was able to find and the second one might actually prove useful. It will be a while before I get back into though, as I don't have a garage and this barrage of rain/ snow is counter productive to working outside.

yo Murph,

Try your local library; some have free on-line access to All Data (Same as Ford EVTM and shows connector numbers and splice numbers), Haynes/Chilton, etc data bases; ours had all data but dropped it recently due to budget. Includes wiring diagrams, etc.