1993 240sx : Horn woes...about to kick myself in the head

[Shift__BODOM]

ok, my horn hasnt worked for god knows how long...probably 2 years...anyway, a while back i noticed that the horn fuse was blown, so i replaced it [didn't think to test it tho] and the horn still didnt work. next, the horn relay. went to a junkyard and picked up another relay. no dice still. my dad was messing with the horn while i was scratching my head and got a wire and touched it from the positive batt terminal to the connector in the horn, and it honked. horns are both fine. read NISTECH's reply in another topic and he wrote out the testing procedure for the horn, and i did it, but didn't get any further than that damned horn fuse. it was blown again and when i probed the terminal without the fuse in, only one side lit up. the side that didn't light up was the left side, with a green wire w/silver dot. what do i do next? i tried testing the relay, but nothing really came of that since my test light isn't long enough to reach from the neg batt terminal all the way across the engine bay to the relay box.

this is mainly for nistech, but anyone else who can help is very welcome to add.

[NISTECH]

Ok see if this helps simplify the system for you

[Shift__BODOM]

awesome drawing!

so, assuming that the green wire runs to the relay, the fuse being blown wouldn't supply the connection between power and relay, thus nullifying any tests done at the relay box since there's no power. right? so the answer should be, "get a new fuse" and now i'm right back to square one. would the switch on the wheel be causing this? maybe the ground for the switch got crappy? my cruise control doesn't work either. i turn the system on at the dash, but the buttons on the wheel do nothing. i think the wiring into my steering wheel is fux0red. could a bad ground in the steering wheel wiring somehow cause the fuse in question to blow? it seems right in my head...

i dunno, am i right?

[NISTECH]

Anything off the line going to the steering wheel from the relay would not cuase the fuse to blow, if that line where to short to ground it would be just like pushing the horn button the horn would constantly blow. But the fuse would not. So you problem has to be between the fuse and the relay or between the relay and the horn. Keep in mind the horn could be drowing to much current and poping the fuse, the relay could also draw to much current on its coil side. What you need to determine here is if the fuse blows only when the horn is ysed or if it blows just driving the car around with out using the horn. The cruise may be a seperate issue.

[Shift__BODOM]

alright, i'm about to go pick up some fuses, so when i replace it, i'll tell you what happens.

[Shift__BODOM]

ok, i put in the horn fuse, nothing. "honked" the horn many times. the fuse didnt blow. drove around, the fuse hasn't blown. put the gator clip on the neg batt terminal and the probe on the power terminal and the tester lit up, then jumped the solid green wire and the horn honked. the fuse is still intact. put the probe on the power terminal, and put the gator clip on the terminal with the green/white wire and pressed the horn button and nothing happened. does this mean that my horn button is messed up? where exactly is the horn button? do you need a pic of the back of my steering wheel cover?
Modified by Shift__BODOM at 2:46 PM 6/5/2005

[NISTECH]

Does the horn honk when its all to gether and you press the button? A bit confused by your post, It sounds as though it did, and by the way your car should have to horns. Pulled up the actual wiring diagram. You should see your test light illuminate when you do it as you did at the end.

[Shift__BODOM]

i know, i've been looking @ the diagram the whole time scratching my head. i can never find the "flow" of electricity in the wiring diagrams. anyway, i jumped the power terminal to the terminal that sends current to the horn with a paperclip, and the horn honked. HOWEVER, when i rigged the gator clip to that G/W wire and the tester probe on the power terminal and pressed the horn button, the test light did not light up. unless i have to "backprobe" it with the relay in, i think i did it right.

now, since the test probe didn't light up during that last test, does that mean my relay is shot, or is there a bigger problem?

oh, when i pressed the horn button (steering wheel) with everything together and the new fuse to replace the blown one, the horn did not honk then either.

[NISTECH]

Ok with those results I am betting something is wrong in the steering wheel area. It looks like you car DOES use the ASCD wiring in conjunction with the horn button. Do you have air bags? If so you need to be carful when removing it. The cage in which the center peice of the steering wheel[air bag or not] is the horn button, when that cage is pushed down it honks the horn.

The next test you need to do [before removing the center of the wheel] is to locate the conector at the base of the steering wheel, inside the coloum covers, locate the G/W wire, disconnect that connector. Ground that wire to the body with a jumper wire. The relay and every thing else should be connected and inplace during this test. See if the horn honks now. If so you have isolated your whole problem to either the clock spring or the harness in the steering wheel.

[Shift__BODOM]

no, no airbags.

so basically, i ground that G/W wire from the harness connector. easy enough. i'll come back later with the results, as it's 3:40 in the morning and i need to get to sleep. muffler shop tomorrow...woo-hoo [/sarcasm]

[Shift__BODOM]

grounded that wire. nothing. key was ON what now

[NISTECH]

This tells you there is an open in that wire between your steering wheel and the relay. This is the tough part, you need to locate where the wire is broke. Unless there is a connector between there and the relay, then you need to check there first.

[Shift__BODOM]

CRAP!

ugh. i guess i'll go look for that wire tomorrow. i dont think there's another connector between the wheel and relay. i've ben glued to the wiring diagram for a whiel now.

woo! its gonna be a late starting day tomorrw..

[lanseeb]

I AM TRYING TO RESTORE MY 240 CONVERTIBLE IT HAS SURVIVED 3 TEENAGERS AND 180,000 MILES, RUNS GREAT AND MECHANICALLY MAINTAINED FOR MY WIFE AND I. THE HORN BEGAN GOING OFF BY ITSELF, I DETERMINED IT WAS THE INSULATION IN HORN PAD ALLOWING THE CONTACTS TO TOUCH. I REMOVED THE HORN REINSULATED THE BAD PARTS OF THE INSULATING PAD, TESTED IT WITH A METER. WHEN I WENT TO TRY THE HORN IT DID NOT WORK OF COURSE. I FOUND THE 10A FUSE WAS BLOWN. I REPLACE THE FUSE AND STILL NO HORN. THE CAR IS GARAGED RIGHT NOW, BUT IT SEEMS THE BATTERY I POSSIBLY GOING DEAD, IT IS NOT A NEW BATTERY SO I DO NOT KNOW IF ITS RELATED OR COINCIDENCE. CAN SOMEONE TELL ME HOW TO TROUBLE SHOOT THIS, I CANNOT MOVE ON WITH MY REFURBISHING TIL I GET THE HORN FIXED, THANK YOU.

WHERE IS THE RELAY. ALSO WITH THE BATTERY OUT OF THE CAR, I DISCONNECTED THE POS LEAD ATTACHED THE BATTERY TO THE POSITIVE AND GROUND TO GROUND THE HORN WEAKLY BEEPED, THEN STOPPED, ITS SUPPOSE TO HONK, KIND OF SPARKED ALOT WHEN I CONNECTED IT, I DO NOT BELIEVE THE HORN IS BAD.

[180fan]

relay boxes up front should have it. Try not posting with all caps. It gets irritating after a while.

[lanseeb]

Here is what I have maybe it will help. I checked my horns they are good and honk. In the steering wheel the bottom plate of the horn pad contact goes to ground-the steering wheel metal, I checked this it is grounded. I have a yellow wire connected to the top of the horn when pushed it contacts the bottom which is grounded. This yellow wire I think is suppose to go to the relay and make up the ground side of the relay, which closes and connects the horns to 12v. I connected my yellow wire to the ground(steering wheel metal) I then removed the Horn relay, there are three contacts, looking down into the socket, the connector closest to the front is at 12v, then one of the other sockets should be at ground from the yellow wire, but I could find no ground or voltage at either of these connectors. I do not understand what is suppose to happen at the 3 relay contacts, if someone could explain this we might be able to fix this. Right now I am inclined to believe I am not getting the ground contact from the horn switch to the relay, I need to know which should be the ground so I can test. If this is the case I do not believe I will dig into my wheel well wiring, I just need to know the correct wire under the dash, may just be a yellow wire but I don't think so but I would find the wire tap in and run this wire to my relay and solder the wire onto the correct relay post?????? I know everytime I take something apart I cannot get it back the way it came, and I like my car the way it is. Now all this could be all wet. Have nice day.

Also I have a 300ma current draw on my battery when car is off, is this normal???????

[lanseeb]

From your electrical diagram can you tell what post does what in the relay and what are the color wires from the steering wheel to the relay?????

[NISTECH]

after no more then 60 seconds your alarm system should go into sleep mode and you should see no more then 50mA draw. Now when you set this up for parasitic load testing your battery can NEVER loose contact even when you are setting up the meter to test it. This is accomplished by placing your neg lead of you meter on the center of the neg battery post and your positive lead on the neg batt post clamp. You then slide the neg battery cable clamp up aroung you testers neg lead until it clears the post. This will give you the most accurate sleep mode current draw test results. Also you need to unplug you hood pin switch if you have one and make sure the key is out of the ignition and the doors are all closed. Then after 60 seconds of meeting that criteria you do the test as I mentioned.

On the horn relay. There is one wire going to the steering wheel, that is your ground, one wire going to the horn and one wire supplying power. That power both energizes the relay and supplys the horn with power. If you dont see voltage with a volt meter on any one of the 3 terminals you have a blown fuse or open wire somewhere.

[lanseeb]

Any luck fixing your horn, I haven't had time to mess, i believe it is a wire problem between the steering wheel and relay, i should have continuity from the steering wheel to relay if not then wire is broke, melted.

[lanseeb]

There is no way I am tearing into the nicely bundled and taped groups of wires, I fear I would do more damage than good, there has got to be a creative solution to this problem, I am going to run a wire from the horn ground somehow to the ground terminal of the relay, horn should blast, right, then if this works, I try and find the wire under the dash, splice and run new wire somehow to the relay, not sure how to do this yet.

[NISTECH]

If you DONT have an air bag, remove the horn pad from the steering wheel and access to the wire is right there. Jump that wire to the metel frame of the steering wheel to see if the horn honks. if it does your horn pad is hosed.