2000 4runner 4wd. So both of my front parking lights weren't working. Pulled the bulbs and they were both burnt out. Bought news ones, put them in and still not working. I did a search about this issue but came up with nothing except parking lights are on the tail light circuit, my tails work fine though. Any ideas? I do have an aftermarket trailer brake controller installed by previous owner.

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Thats odd, the circuit is pretty cut and dried, check for power, check for ground. Any modifications or body work done recently?

Having this exact same issue on the '98 we just "finished" building. All lights work fine except these side markers. Pulled them, bulbs are fine...swapped an entirely different "base" (part that goes in the housing) in with a know good bulb and still nothing.

I stuck my multimeter in the connector and see just under 12V DC and it drops to zero when we turn them off on the stick. We have power....just no lights.

Thoughts? Do I need to check ground and if so...any advice?

That's interesting - I had the same issue on one side of my '97, no light. I put in a spare bulb, still nothing. Went through three more spares, thinking maybe they were all bad (they were leftovers from when I put in LEDs in another vehicle), but none worked. The fifth one did work, so I assumed the others were just duds. Now I wonder if there's a bigger issue of insufficient current capacity in the wires.

Your post reminded me of a light bulb moment (no pun intended) I had years ago on another car. I was trying to figure out why a circuit was not working, even though I was measuring 12V at the device.

After much head scratching and cursing, I found corrosion in the wire bundle, such that there was enough current carrying capacity to measure 12V, but not enough to actually power the device. Ever since then I remember to not just measure voltage, but to use a bulb tester to see that the wires can actually turn on a bulb. It sounds like this may be the issue in your case.

Hope this helps.

Sorry for the ancient bump, but this fixed the issue?

I just replaced my headlight assemblies with the '99+ plus lights and now my marker lights don't work. I did notice that the headlight connectors were VERY corroded so they're going to need to be replaced anyway. I'm really hoping this solves it.

Oxidation of wires creates resistance. The resistance reduces current flow. So when enough oxidation occurs your bulbs cant get enough current flow to function. Happens all the time on older vehicles.

So if everything is looking right 12v at the socket. It's best to check the wires for continuity. These wires should be very low resistance and tone in a continuity test with multi meter. Oxidation is bad. Try to keep all connections clean and coated in conductive grease.

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