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One Taillight Not as Bright as the Other
- Thread starter THIRTY2
- Start date
The left side almost looks like the brake lights are on. Maybe bulbs were forced into the socket wrong? Are all the bulbs the same? How do the lights look when the brakes are on?
Or could be a bad ground connection on the right side.
Or could be a bad ground connection on the right side.
Agree, it looks like something is causing the brake lights on the left side to stay on. Faulty ground or corrosion in the trunk wire harness connectors.
This is common, there are threads on here that discuss how the right rear tail light harness is actually the "caboose" for the cars electrical system, hence the lower volts. Once you see it you can't unsee it and now when you peruse NSX galleries you'll notice it a lot 
. Those that have converted to LED no longer seem to have that issue but it introduces other things you'll need to address (brake warning light indicator, LED load equalizers, modifying relays, etc.).
. Those that have converted to LED no longer seem to have that issue but it introduces other things you'll need to address (brake warning light indicator, LED load equalizers, modifying relays, etc.).
Agree- for some reason Honda did not use the weatherproof connectors here. Puzzling since the trunk can get so swampy when the tail light seals fail.This is common, there are threads on here that discuss how the right rear tail light harness is actually the "caboose" for the cars electrical system, hence the lower volts. Once you see it you can't unsee it and now when you peruse NSX galleries you'll notice it a lot
The caboose on the train metaphor seems to imply that the right side is tacked on to the end of something. Not an exact metaphor; but, not completely in error either The right side and left side tail lights are on completely separate circuits, fuse 39 for the left side and fuse 38 for the right side. When you look at the diagrams in the ETS, the left side tail lights are the only thing on fuse #39. When you look at fuse #38, there is a pile of other stuff connected to the fuse #39 circuit. However, most of that other stuff consists primarily of the little light bulbs that illuminate things like the switches. The big extras would be the front parking lights, the rear side marker lights and the license plate lights. In addition to these extra loads, the right side tail light circuit has more connectors in the circuit before it finally makes it to the light bulbs in the tail light.This is common, there are threads on here that discuss how the right rear tail light harness is actually the "caboose" for the cars electrical system, hence the lower volts. Once you see it you can't unsee it and now when you peruse NSX galleries you'll notice it a lot
That said, having read this post I had to go out and have a look at my car and I do not find an obvious difference in the tail light illumination between the left and right sides. I suspect that for @THIRTY2 's car, @Honcho 's comments may be more relevant that there are connection issues at play. It is hard to tell whether the center and two outside lights on the right side have different illumination levels. If they are different, then socket connections at the individual lights might be an issue.
Given the moisture issues, I would also be inclined to look at C560 for the right side tail lights because it has a common + and ground connection that affects all three bulbs in the housing. There is a common chassis ground; but, the ETS says that it is common with the left side so if the left is bright and the right is dim it is likely not the chassis ground. I suggest that THIRTY2 purchase a bottle of Caig Deoxit D100L and apply a drop or two to all of the easily accessible electrical connections including the light bulb contacts. The marketing for this stuff reads like snake oil; but, in this particular case the stuff does seem to do pretty much what it claims to do.
I have embedded the fuse diagram for the tail light supply and the wiring diagram (the fuse diagrams do not show the ground connections) for the tail light supply. The latter shows all the extra connectors in the right side circuit which gives you lots of places to apply the D100L should you wish to explore repair options.
Thank you Old Guy, that is an enormous amount of good/helpful information. The far right bulb on the RH taillight does seem to be the dimmest of the three. I will try the deoxit suggestion and see if that helps. For what it’s worth, the car is stored in a climate-controlled garage and has never seen rain during my 5-year ownership and I would venture to guess not during the previous owner’s tenure either.
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