After opening the front of the steering wheel, the connectors for both the airbag and the horn don't have any power- where does it come from? Also, the fuse works, and I'm not sure where the horn relay is, so if you could tell me, that'd be great.

 

What do you mean by the "front of the steering wheel"? The top and bottom covers that are behind the steering wheel covering the column or did you remove the airbag?

If airbag, you removed the negative cable from the battery and waited 10 minutes, right?

Anyway, if your horn isn't working, it's possible that one of the leads in the clockspring is bad. My horn wasn't working when I got my 95 and it turned out to be the clockspring. The steering wheel has to be removed to replace it.

Here is a picture of the clockspring behind the steering wheel with the airbag removed:

https://www.clublexus.com/forums/ls4...ing-wheel.html

One of the 6 leads on the connector at the top is for the horn. You'll have to check continuity from the front connector to the back. It's either pin 1 or pin 6 but if either don't have continuity, then the clockspring is bad.

As for the horn relay, it's either down by the emergency brake where the other fuses and relays are or it's under the hood. My car isn't here now so can't check.

Oh, welcome to the forum as this is your first post. You don't mention what year you have so it would help to put it in your post or subject line. Also, this forum has a ton of good posts discussing just about any problem you will come across. When you're looking at the forum index, there is a link for "Search this forum", enter a keyword or two and to find them, "horn relay" or "clockspring" will get you going.

 

Oh, sorry. I drive a '90 LS400, closing in on her maiden 200,000.

I removed the airbag and tested the connectors, but they didn't read anything. I tested the fuse slot and got nothing.

More questions: why do I have to remove the negative cable, and what is a clockspring and its purpose?

As for the given suggestions, I will attempt them.

EDIT: My car does not have a clockspring. Again, can someone point us towards where the horn relay is? We (my family and I) believe it's the problem.

 

The horn relay is in the fuse/relay box under the hood.

ALWAYS remove the negative battery cable and wait 10 minutes before messing with the airbag. It's standard operating procedure. You don't want it going off in your face as you disconnect the cable, do you? Seriously, this is a must. Do so before connecting it back.

Yes, your car has a clockspring, ALL cars have them. If yours doesn't than there's your problem. Here's one listed on eBay: LINK

As you already have the airbag off, you should see a yellow cable and the 6-pin connector in the picture I posted in the other link, right? If so, that's your clockspring, otherwise known as a spiral cable assembly. Remove the upper and lower column covers and find the connector on the back side of the clock spring and remove it. Check continuity between all the pins (corresponding front and back pins).

But before you do that, here's another thread with some testing procedures:

https://www.clublexus.com/forums/mai...n-problem.html