I have a 1992 Honda Civic lx and when i hit the horn it clicks i check the relay and it just clicks so i tested it with a jump cable and one side of the plug has full power but the other mouths dont what could be wrong

Without testing who knows . Do you know what a automotive electrical diagram is ? How to test electrical circuits using a volt meter . Free wiring diagrams here http://www.bbbind.com/free-tsb/ Enter the vehicle info. Year , make , model etc.... Under system click on interior & driver amenity ,then under subsystem click on horn . Click the search button then the blue link . Looking at the wiring for the horn i see a whole bunch of thing's that could go wrong . Fuse , relay , wiring , the horn it self , the cable reel inside the steering column ,other wise called a clock spring. Does the car have a air bag light lit on the instrument cluster ? Videos on youtube. showing how to test horn circuit .

https://s1.postimg.org/2d16m362ov/horn.jpg

Click on the link. Horn wiring, non-hybrid. The relay is part of micu, multiplex integrated control unit.
I don't believe the relay is removable. You can check the fuse. Not only check the fuse, use test lite to check voltage on fuse circuit. There are several things you can do to see if horn will sound. I couldn't get everything in the one picture. The horn shows a one wire connector, you can take connector loose, use jumper wire connected to B+ to see if horn will sound? You might use an inline fuse, just in case. Your horn switch is just a ground for control side of relay.
I can't diagnose the micu, itself?

In the fuse box under the hood or in a box behind glove box.

These are the classic symptoms of a defective ribbon coiled contact under the steering wheel called the Clock Spring (also called a Cable Reel) being defective, one or more of the circuits on the ribbon coil is open, this is a very common failure. If you follow the link you can read about how to replace it at a Honda owners forum. Clock spring replacement Honda Civic Forum

Honda Civic Coupe Questions - car will not start. battery ok ...

www.cargurus.com > Questions > Honda > Civic Coupe

CarGurusJul 9, 2008 - Get someone to turn it over and see if it is getting spark. ... i have the same issue with my 1993 civic lx it has a 1.5 sohc non-vtec i changed ... comes wen the 2nd click of the main relay it doesn't occurs until after few minutes, few .... My 2000 Honda Civic Ex Vtec will not start, has a new tps, new throttle body, ...

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troubleshootmyvehicle.com > Honda > 1.6L

Dec 31, 2012 - Difference Between a No Start and a No Crank Condition. ... can cause your 1.6L Honda Civic (Civic del Sol) to Crank but Not Start. ... In other words, the engine doesn't turn over at all. ... 1995, 1996, 1997, 1998, 1999, 2000.

98 Honda civic won't crank (PushStart) - YouTube

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https://www.youtube.com/watch?v=X5W7OqjKB8I
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With the key on but not the engine, press the horn ring a listen for a click, that click is a horn relay. You may need someone to listed under the hood for you, If you don't hear the click, take the covers off the fuse box and see if there is a diagram for the relays that shows a horn relay. While you are checking, look for a fuse for the horn. In rare cases it could be the horn ring or the clock spring.

Check brake pedal switch which kicks out of cruise when you hit the brakes. These jump out of place easily so check that it is depressed when pedal is released (up).

this is covered in the FSM, buyone
or look at alldata.com under windows.
that's funny you need windows to see and fix windows in car, LOL

main fuse beside battery

The relay (or possibly a fuse) should be located in the fuse/ relay panel in the engine compartment. The lid of the panel will (most likely) have a map on it showing the designations of each individual relay and fuse.
Hope this helps!