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Discussion Starter · #1 ·
My tail lights keep blowing the 20 amp fuse, have pulled all the connectors, still blowing fuses, my 96 has 97 bulb holders uses a 3157 bulb where can the problem be
 

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dshirley, where did you find what bulb you needed?

I had a tail light issue and was looking for anything related and found this. My rear left turn/brake light went out (I thought, it just worked loose), so I looked at the Sylvania book and it told me it required the 2057. I didn't think twice about it, although I did double check to make sure.

So I bought them, get home, take the assembly apart and THEY DON'T FIT. Totally different bulb setup. I checked on Sylvania's website and it says the same number (2057). But I did a Google Image search, and found the same bulb that's in my truck. What dshirley mentioned above, the 3157.

Now I'm wondering what's going on.
 

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Discussion Starter · #3 ·
Its a 97 harness on a 96, late in the year dodge started doing this, my problem is when I turn on the head lights it blows the fuse on the tail lights.
 

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I see. I have no idea about your issue with blowing fuses. Although I'm more of an electrical or computer guy, but I may be able to find something out if I go out and poke around. I'll be messing with it later.

Thanks for the info on the 97 harness. That makes sense, though I wish there had been a note somewhere in the Sylvania book or on the website.
 

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dshirley, where did you find what bulb you needed?

I had a tail light issue and was looking for anything related and found this. My rear left turn/brake light went out (I thought, it just worked loose), so I looked at the Sylvania book and it told me it required the 2057. I didn't think twice about it, although I did double check to make sure.

So I bought them, get home, take the assembly apart and THEY DON'T FIT. Totally different bulb setup. I checked on Sylvania's website and it says the same number (2057). But I did a Google Image search, and found the same bulb that's in my truck. What dshirley mentioned above, the 3157.

Now I'm wondering what's going on.
They are the same amperage (2.1a and .50amps) but different base configurations.
Two separate circuits for each dual filament bulb.

20amp fuse: for signal/braking, Goes into the turn signal switch/flasher.

15 amp fuse: for parking lights (goes into the headlight/park light switch)

If the 20 amp fuse blows..probably a short somewhere because the 3157/2057 in themselves
only draw a maximum of 2.1 x 4 lights (8.4 amps).
 

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Its a 97 harness on a 96, late in the year dodge started doing this, my problem is when I turn on the head lights it blows the fuse on the tail lights.
The 20amp fuse goes to the combo multi-functions switch and the flasher, you may have a problem there.
 

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Discussion Starter · #8 ·
No, the headlights work fine, the dash lights and the tail lights are the only things that are effected
 

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No, the headlights work fine, the dash lights and the tail lights are the only things that are effected
Sorry, I didn't provide the full dual filament explanation.

Ok, according to the wiring diagram for rear lighting on my 1998 Haynes service manual, the +12V comes from the PDC into the 20amp fuse, then it goes to the combination flasher.

From there it goes to the multi-function switch ( ie: turn signal stalk switch: (flash to pass/low beam/windshield wiper/washer) etc.

The multi-function switch portion that is affected, will have the combo function (flasher/hazard ) relay
and the O/P of the turn signal stalk switch, going the front left/right turn signal lights AND
rear left/right turn signal/brake lamps.

The brake lamp switch (when operated by the brakes) has it's own battery, and goes into the multifunction switch and high center brake light. Inside the multi-function switch, a set of contacts provide the +12v brake to the rear left/right turn signal and stop lights. So even if you are signaling a turn and the flasher is operating the bulb for the direction
you are turning, if you hit the brakes, the brake switch battery will override the flasher, and the light will be
on steady during braking.

These are dual filament bulbs, so for the parking, license plate lamps and marker lamp functions come in from the headlamp switch via a 15 amp fuse. This circuit is independent of the other one above.
 

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seem like u have short to groung somewhere on that circuit have u checked the conitunity on the wires and traced the circut via a wiring diagram
 

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Discussion Starter · #11 ·
Im back with the same problem, when I turn on the head lights, the fuse for the tail lights and the dash lights blow. The turn signals work and the brake lights work, is there a good wiring diagram available,
 

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Im back with the same problem, when I turn on the head lights, the fuse for the tail lights and the dash lights blow. The turn signals work and the brake lights work, is there a good wiring diagram available,
The tail lights are fused by fuse 14 (junction block) 15amp. After the fuse
the +12v goes to the headlamp switch (off/park/headlamp) and then to
JOINT CONNECTOR #1 in the PDC. There is a takeoff there for trailer
tow lights (Joint connector #2) and the trailer tow relay in the PDC.
The tail lights work off that through a splice (S316).

If the tail light fuse is blowing right away, more than likely may have some kind of short on the wire(s) going to the tail lights.

Take out the tail light bulbs (one at a time) and see if that isolates the
problem...as the fuse will only blow if the tail light is drawing current
from the fuse.

The Haynes manual for the year of your truck will have all the wiring diagrams..
that is if you can read them.
 
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