Hello I will help you with your question,
I will tell you up front that I have never disassembled one of these but it looks like you remove the cover of the horn shroud can be pryed up and then the screw securing the horn switch removed. If you have the LS model the screws are removed.
The horn switch can be tested at that point to see if it is the switch or the contct ring under the wheel that is the problem. You would mark and remove the nut from the column and use a steering wheel puller to get to the horn contact ring
It may be cracked or just dirty.
Click here for expolded view
The horn wire is green and grey depending on which horn you have, I would put a testlight to the horn connector before disassembly and push the horn switch to see if it is the horn itself that has failed.
Let me know what I can do to help
Check the power at the horn connector itself before you disassemble the steering column. It may be that the horns have failed or the ground for the horns are bad. A $5 testlight check can save a lot of work if the problem is at the horn.
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Just let me know what I can do to help
Thanks George, the first part of this went okay. This IS an "LS" Model Isuzu Pick-up. I pryed and got access to the switch. The spring action, springs and wire connections all seem fine. I used a test light at the connector and got nothing for a current or power.
If I understand the next direction and "exploded view", I am to remove the nut, and pull the wheel with a puller. I have not done that before, but it seems simple enough. Mark the nut and wheel location, remove nut, use puller (either to be purchased or rented) and remove sterring wheel. I am to check the condition of the "horn contact ring", and either clean or replace as necessary....right? Thank you!
The connection for the horn on the steeing wheel switch is just grounded to the column to sound the horn so you can try to sound it that way.
You should have two connectors at the horns? No power there?
You should have power to one side and the horn switch grounds the other.
If you have to take the wheel off you have the sequence right.
I would post the wiring diagram but it is hand drawn and very hard to follow.
Get power to the horns first and then you can use the testlight to see if the horn switch is grounding the other contact by puttin one lead of the testlight to a power source then touching the non power side of the connector.
Well, we're making progress. I was able to check power to the horns (there are actually 2-horns on separate brackets, 2-wires each: 1-green, 1-green w/red stripe). There IS power to both horns. I was able to jump the wires and actually sound BOTH horns.
I suppose that leaves the contact ring (dirty or damaged) underneath the steering wheel as the cause for the horns not to work? So my next step is to pull the wheel and check, right? By the way, the truck is over at my Parent's house so I do not have the easy access to it like walking right out to my garage. Thank you!
I would install the test light in one of the connectors and start working my way down the wire at the base of the column, find the green wire and ground it by piercing the insulation with a straight pin and using a jumper to a clean ground, you should be able to sound one horn and light the light this way. If you can then the problem is up in the column and you need to pull the wheel, if you cannot sound the horn/light the light then you need to move closer to the horn and try again. This will keep you from working on the column when the problem is between the column and the horns.
Hi George, I hope you are there today...this is the day this horn issue finally gets resolved...I hope! With the outside weather in the high 30's here in the Lake Tahoe area I finally my Dad's truck inside my heated garage with all of my tools.
A few days ago I was able to test and jump the wires at the base of the steering column and the horn worked fine. Today I have a borrowed wheel puller (easier than I thought) I have the steering wheel off and column shroud off so I have access and visbility to almost everything. This is what I have found:
1. Brass colored contact (Part #5 on Exploded Drawing you first sent me) is intact and appears in good condition. I did remove it, wipe it down, brushed up the surface with a steel toothbrush to clean any film of the surface. I also disconnected the spade wire connector, cleaned, tighten and replaced. All reassembled.
2. There is a spring loaded brass fitting (looks like the spring of a push-buttoned ballpoint writing pen) that makes the contact with the brass contact ring (Part #5) and must be the problem. After placing the steering wheel back into place and pushing the horn, sti8ll no horn. When I remove the sterring wheel and just jump the brass spring to the splined shaft of the steering wheel (it must be the ground) the horn sounds!!!!
So with nothing seeming to be broken, why/what is the reason that electrical contact to sound the horn is no being made? What's next......????
Can you install the horn switch and contact without the steering wheel?
I know some of these had a plastic bullet connector that you turned 1/4 turn to lock the spring contact in place.
If you can install the contact you are working this the right way, keep sounding the horn (or install a testlight in place of the hore if you have neighbors) as you work your way up to the switch. Somewhere along the way you are losing contact.
As a last resort I have installed a large white horn switch on the dash and tapped into the horn wiring at the base of the column. Some states will not allow this so if you are registered in California I don't think it would fly but in Nevada it might.
Sorry I cant be more specific I posted all the drawings of the connection and assembly that are available, maybe if you can post a picture of the connection with the spring I might have a better suggestion.
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Let me know what I can do to help you with this
Okay...this is wierd! I have always suspected that some parts of automotive maintenance besides training and experience, is a little magic and luck!! I went back to the exposed column and the underside of the wheel. A little touching, a little wiping, no when the steering wheel is placed pack on the column, the horn pad is sounding the horn just fine!!! I've turned the wheel, it works, I've touch the horn pad intermittetly, it works....what did I do? Should I expect this to work after a reassemble the column shroud and the sterring wheel? FYI - on this Isuzu, the contact ring is attached by 3-screws into mounting points on the underside of the steering wheel.
Any other thoughts...???
You can try cleaning all the contacts with electrical component cleaner and using a little di-electric grease to keep them from corroding. Afret all these years I suspect that there is a film of corrosion that is keeping the column from being grounded to allow the horns to sound. The column needs to be grounded to the body so a redundant ground wire would not hurt from the mounts to a clean piece of sheet metal.
All you can do is try it at this point and if it works reliably once assembled drive it around for awhile and try again to be sure.
You found how easy it is to disassemble this so if it stops you are in the right area and it won't be hard to chase down.
Sounds good! Thank you so much for you patience and assistance with this issue. I have never used this service before and would definitely consider using this again. I'm done with this problem.
Thanks again, Happy Holidays!!!
Glad to help and I hope you get it working reliably, I hate those aftermarket horn buttons!
Let me know if there is anything I cann do to help you
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