Where is the tail light fuse for a 2003 pontiac montana? Bulbs are fine, both just suddenly stopped working.

Most likely the multi-function switch (head light switch).

What you are saying is the parking light on the left side does not work.
The parking and stop lights are on different circuits.
If you have replaced the bulbs the next step would be to check for voltage and ground in the socket.

Check the adjustment on the brake light switch directly above the brake pedal

The circuit board witch holds the tail light bulbs could be at fault,check the voltage to the tail lights when this happens,if there is none,replace the headlight switch.If there is voltage to the tail lights,replace the tail light assembelys

The working light bar reveals that the brake switch is working, and the fuse is good. Check the bulbs, they are probably burned out. If not the bulbs, then the wire that goes from one side to the other may have failed.

you have a bad brake light switch

It's most likely a relay under the hood, have u checked them?

check the tail light circut boards. mine melted and had to replace them

Tail lights acting insane?

We had the same issue with our 2000 Pontiac Montana. Brake lights, turn signal lights, running lights, back-up lights and emergency flasher didn’t work at all or operated at random. The cause: poorly designed aluminum contacts on the tail light circuit board and wiring harness connector arced over and disintegrated with normal use.

Pull the tail lamp assembly, remove the electrical connector and look for burned contacts on the connector plug and the connector socket (they call this long plastic piece with the socket the circuit board: it includes the four bulb sockets. Replace the circuit board and the wiring connector.

You can DIY this job with basic auto mechanical/electrical skills and tools. The two circuit boards and the two connectors set me back $230 (2009 cost) for new parts. The electrical contacts on the factory replacement parts are improved.

I needed a T-30 torx driver to remove the tail light assembly (you need this to change out bulbs, too), wire cutters, wire strippers, electrical tape and an electrical lug crimper to do the job.

At:
http://townhall-talk.edmunds.com/direct/view/.f101976
found this discussion which might be helpful:
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No surprise at all! Common problem which has been discussed several times on this site.
Basically.....tail light(s) plugs (Pig Tails) were sub-standard and cannot stand the heat of the bulbs. Pull out hear tail light fixtures, remove bulbs from recepticals and check for melting plastic, usually between the black wire (hot wire) and one or more colored wires. If so, cut out old Pig Tail, get a replacement Pig Tail, soder it in (I think about 6 wires), and use electrical shrink wrap around sodered joint, install new bulbs using Di-electric grease in the socket. Test before reinstalling light fixture.
Jack
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The poster also mentioned something I forgot; use some kind of grease in the sockets any time you have reason to access them.

The dielectric grease he mentioned is best but if you can't find (it is and electronic item, rather than electrical), even petroleum jelly will afford some protection.
I use it on battery clamps and it helps ****** the typical corrosion.
Since most cars use the chassis for ground, even the fasteners that hold in lighting assemblies can lose contact so I always loosen, then retighten them, to ensure decent ground contact.
Check too for corrosion in the light sockets themselves.

Dunno why it is so tough to seal a compartment but our US manufacturers can't seem to get it right.

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