Mechanics

F150 FUSE BLOWS

1991 Ford F-150

Electrical problem
1991 Ford F150 V8 Two Wheel Drive Automatic 77012 miles

The # 5 (15A) fuse in the fuse panel below the steering wheel keeps blowing. It is for the turn signal, back up lights, and overdrive switch. It will work fine for a few days then it will blow usually when I am driving fast. There are 2 wires leaving the fuse: 1 for turn signal & back up light, 1 for overdrive. Without the signal on or the back up lights it draw constantly 1.05 amps. With those 2 on it draws below the 15 amps. Is this normal what's the best way to find the short.

Thanks ahead, Tim
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Zip dog
April 5, 2009.




Hi
Mitchel shows #5 as courtesy lights, dome, cargo and glove box. #3 is turn, backup and OD.
Recheck let me know

Thanks for donate

Docfixit
Apr 5, 2009.
On the cover panel it says it is # 5 and not to mention when I replace it the turn, backup, and OD work till it blows again. -Tim

Tiny
Zip dog
Apr 6, 2009.
I found that it is the circuit to the dir Flasher that draws at a start 2.6 amps then after about a minute 1.2-1.05 amps. From Mitchell's Fig. 6 Fuse Block (grids 20-23) it looks like it may be the back-up lights or switch?

Tiny
Zip dog
Apr 6, 2009.
O.K. Truck is wired like a 1990 so maybe backup or see the O2 sensor it is a heated sensor that might be the problem. If it was turn, OD, backup should blow when used. 15 A too high see what just the backups pull?
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Docfixit
Apr 8, 2009.

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