1993 Ford F-150 no brake lights

Tiny
MIKE L
  • MEMBER
  • 1993 FORD F-150
  • 5.0L
  • V8
  • 4WD
  • AUTOMATIC
  • 150,000 MILES
Hi, all the other lights work. The key is not in. The truck does run. I have unplugged the two plugs at the rear bumper to the rear lights, the mufti-function switch on the steering wheel, the 21 pin plug going through the firewall and the headlight switch. There are two plugs at the bottom of the steering wheel. The one plug that turned off the lights in the cab, I left plugged in. I was told it's a bad ground. I have cleaned the two ground at the kick panels. It blows fuse number 13 when I press the brake. What are some things I can check next?
Thanks, Mike
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Wednesday, April 22nd, 2015 AT 11:50 AM

10 Replies

Tiny
HMAC300
  • EXPERT
Check for a short in the wiring going to the brake switch then to lights. Probably along frame or where it goes under truck. Check ground at center rear cross member and probably rear of truck. Also org/lt blu and lt grn/org wires for lights. That is more than likely your problem.
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Wednesday, April 22nd, 2015 AT 12:21 PM
Tiny
MIKE L
  • MEMBER
I checked there are no grounds wires under the truck. Does it help to unplug all the plugs? I plugged everything back in and I found the one that causes the fuse to blow.
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Wednesday, April 22nd, 2015 AT 3:00 PM
Tiny
HMAC300
  • EXPERT
Then trace the wires going to that plug it has to be hitting someplace.
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Wednesday, April 22nd, 2015 AT 3:25 PM
Tiny
MIKE L
  • MEMBER
Thanks, the plug has four wires, and is located in the center of the dash. Do I trace the side that doesn't have power because it blows the fuse only when it's plugged in? With (everything) unplugged except for this plug and the plug at the bottom of the steering column ( which controls the ceiling lite) it blows the fuse.
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Wednesday, April 22nd, 2015 AT 6:15 PM
Tiny
HMAC300
  • EXPERT
Ya test it where you found it get a circuit breaker from auto parts so power will go off and on if you have a small compass run it along the harness to find the problem area. I think it's your wires for lights in back.
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Thursday, April 23rd, 2015 AT 6:43 AM
Tiny
MIKE L
  • MEMBER
Thanks Do you mean just a fuse circuit breaker? I saw on line a large red device with two leads then you add a test light to it. When the circuit breaker resets the light comes back on for a second to show you still have a short. What's the larger device called exactly I cant find it listed at the parts store. Maybe it cost to much, for a one time use. It said it comes with a simple amp meter you run along the wire bundle.
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Thursday, April 23rd, 2015 AT 9:44 AM
Tiny
HMAC300
  • EXPERT
Yes a fuse circuit breaker a 20 amp one will be sufficient where it won't damage anything. Auto parts should have that
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Thursday, April 23rd, 2015 AT 12:00 PM
Tiny
MIKE L
  • MEMBER
Thanks, the connector that I found has four wire colors that don't match the fuse circuit I'm on. How could this cause my fuse to blow and not other fuses?
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Thursday, April 23rd, 2015 AT 1:12 PM
Tiny
HMAC300
  • EXPERT
Because they change color sometimes going to another area. I think you should have a pro do this. I have no further comments or suggestions.
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Thursday, April 23rd, 2015 AT 1:35 PM
Tiny
MIKE L
  • MEMBER
Thank for all your help!
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Thursday, April 23rd, 2015 AT 1:41 PM

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