Okay. I took my '90 Accord into the shop for a bumper to bumper inspection after buying it for $900 a few weeks ago. Overall, the car is in great shape. They did tell me that I had a tail light out, so I asked them to go ahead and fix it. Hours went by, and they told me it's not something they could fix right away, because it needs a whole new assembly and nobody on the island has the part. (Kauai, Hawaii) So I ordered it online and now that it's here, I'm looking at this thing, and it's just a piece of plastic! How is this supposed to fix my problem? Am I missing something here? I checked the light bulb and it's fine. I checked the fuse and it's fine. Please help me figure out what to do from here.

 

On the first - helps to post a photo.

On the second - did you check for yourself that the tail light / brake light is out?
On my '92, when my son was using it and a tail light (or brake light?) went out there was a dash warning light that glowed. actually it didn't go out just developed a bad contact in the bulb socket (son screwed around with it [small screw driver I guess] and made it OK & then put in new bulb to boot).



Car sounds like good purchase; welcome to the forum.

 

It may be the brake light failure sensor being referred to. There are two light failure sensors in the trunk area; the left sensor (usually brown) is for the left outer and inner brake lights, while the right sensor (usually black) is for the right outer and inner brake lights, and high mount brake light.

The brake light failure sensors are use to help indicate if a bulb burnt out, and power has to go through it to the brake light bulbs. The sensor components may go bad or solder joints crack with age/use; where power no longer goes through relay coils inside the sensor to the brake light bulb.

You would have to remove the taillight assembly by removing the nuts at the perimeter of the taillight assembly. Disconnect the bulb connectors and sensor connector first.

After the taillight is out, you can access the two mount screws for the sensor.

 

Here are a few more pictures I found to help understand removing the taillight assembly. If you unplug that one connector, you don't have to disconnect the bulb connectors and the connector to the sensor before removing.

It should be 4 nuts holding on the tail light.



You'll have to gently pry off the the plastic harness clip from one of the corners that cover a nut.

 

On your 1990 Accord, you'll probably have to remove the plastic trunk liner panel to access some of the taillight assembly mounting nuts.

The plastic liner is usually held on with clips. Looks like there are possibly at least two plastic clips to pry out first. Then pry/pull the whole rear plastic panel liner off (the non-visible clips should come off with the panel).

 

This is what I have

 

Okay, no need to remove the whole trunk liner panel.

You can unplug that one connector first. Probably have to cut the outer electrical tape, not all the tape, to free the harness wiring. (See image.)

Then remove the mount nuts. They should not be too difficult to loosen.

 

Okay I can't do it yet, I'm at work til later tonight. But once I do that, do I need something special to test the wires?

 

I thought you already got a replacement brake light failure sensor. If not, don't remove that yet.

1. Do the taillight light up with just the headlights on?

2. Take a look at the bulbs first. They should be dual filament, check to see that both filaments on each bulb is intact. One filament serves as the brake light, the other filament serves as the taillight. If the wrong bulb was used, that will also cause a problem.

3. If you don't have access to a multimeter, I can try to think up some other test by just jumping some wire terminals to see if your brake lights work.

 

This is what came in the mail after ordering the new tail light assembly. That's why I'm confused. Did I order it wrong, or did I get screwed?