So now my brake lights and reverse/back up lights won't turn on, even the light above the rear windshield won't respond to brake or reverse. Everything else works though running tail lights, blinkers, parking lights, headlights, etc.

The only thing I remember doing a few days ago were replacing my front windshield motor, and cleaning the ground screws and wires under the hood but they are still in place. Also I took apart the dash to clean off the back of the control cluster.

I heard there isn't a fuse for the lights on a 98 sport, so what else is there that I can do?

 

Well the reverse light sound like the NSS, probably time to clean it.
Here is a snippet of the diagram for my 99.. Look under the hood by your battery, black box lots of fuses..

 

The fuses are fine. Does the NSS have anything to do with the break lights as well? Both the brake and reverse cut off at the same time I believe. The thing is the tail lights and blinkers still work in the back.

 

Bump, need to fix soon.

 

Try inspecting wires and grounds in the rear? Sounds like something shorting or a bad ground....And probably a dumb question, but did you check the actual bulbs?

 

do you have a trailer harness? it sounds like some chaffed wires somewhere near the back. definetly check bulbs first and start following the wires back. you'll need a test light to test for power and ground. without knowing which one you are missing you wont know what to look for. figure out which one you dont have and go from there.

 

No trailer harness and the bulbs are good. I just can't figure what could have been damaged while swapping out my feont wiper motor and cleaning the ground connections under the hood.

 

Hate to say it but if everything was fine prior I would go back to all the places you were and check everything again..

 

I just went back and checked everything and can't find any dislocated wires. Having the tail lights and blinkers working but not the brake and reverse lights should narrow something down but I don't have enough knowledge with this car to know.

 

At this point I would say you might have two different issues.
I would meter the brake light switch and see what you get. Auto or manual trans?
For an auto back up against something or have somebody watch as you shift from P to D and see if there is a flicker on the reverse lights.. That would indicate NSS. Which it probably is unless both your bulbs are toast. Can't tell you about a manual, I'm lazy and always go automatic...

 

Time for some circuit splitting.

This is a standard troubleshooting technique in electronics, and it works quite well in other applications, too.

Start by getting a diagram of the circuit. Since you know fuses are good, and the bulbs are good, pick a point in the circuit that's about halfway between these two points. When I say halfway, I mean either functionally, or physically. (I prefer functionally.)

Test that point. If you have the correct reading there, then you know the problem is downstream of that point. If you don't, you know it's upstream.

What's upstream and downstream? The lights are the downstream end, the battery is the upstream end.

So, for example, if the problem is downstream of that point, pick a new point halfway between the bulbs and where you are. Test again.

Repeat as needed until you find the fault.

It's a much more certain method than jumping around from here to there, randomly.