CAR HORN
Car horns can also cause car electrical problems although not that often. A car horn problem is both dangerous and annoying.
Dangerous in terms of not being able to send a warning signal on time, annoying as without a car horn, it’s like you turned “mute” on the TV.
The position of the car horn (although protected in most cars) makes it susceptible to moist, filth, dirt or else. Extensive, abnormal use and material fatigue (in older cars) is also a common reason for these types of car electrical problems.
Symptoms of a faulty horn
These are some symptoms which you’ll come across when the car horn isn’t working:
i. Check Power supply to the car horn: If there is a proper power supply, take of the horn and try to adjust it. Adjustment didn’t help? Then it’s probably time to replace the car horn. If there isn’t a power supply, then
ii. Fuses: check these first before dismantling anything, one of the most common reasons especially if you’ve used the horn extensively. First place to look if there is no power supply to the horn.
iii. Car horn connection (check for a broken, filthy or corroded connection): Once you’ve disconnected the horn look at the connector(s). If they are corroded and oxidized this could cause a problem. This goes double for pin connectors.
Use some WD-40 spray or other connection sprays and try to clean it. If there is too much damage, best replace the whole connector. You can either buy a new connector (as same as the old one) or cut the original one out and replace it with separate, old-school type ones. Just make sure to insulate them properly. The repair will surely last longer if you buy the same connector as the original one.
iv. Horn switch on the steering wheel: This problem usually appears gradually. In the beginning, when pressing, only some parts of the horn switch react (left, right, upper or lower). In time, it stops working entirely. Simply, the contacts inside wear out or get dirty. Also, if the switch has been subdued to physical damage (like hard pressing or banging) it can malfunction. You’ll have to take off the car horn switch for this repair. It’s mostly done by either pulling the switch out of the steering wheel or by releasing hinges or screws from the backside of the steering wheel.
Best Google this procedure for your type of car in order to save time and avoid damage.
The car horn switch in most cars is also a casing for the air bag so be careful when taking it off. Keep the ignition turned off or even better take the minus terminal off of the car battery and wait for 15 minutes or so.
I would advise taking the battery terminal off as it’s the safest. This way you’ll surely avoid the air bag accidentally blowing in your face and injuring yourself.
Once you’ve taken it off, make an inspection of the parts, If there is dust and grit on the contacts and connections, best use a clean cloth, some contact spray or some fine graded sandpaper and clean everything up.
If the switch itself is faulty, best replace it completely, some switches can be taken apart and fixed, but this is mostly on older car models without air bags.
You’ll also find a wire from the switch to the steering wheel, check that connection also.
v. Car horn relay: Relays burn out rarely. Mostly if the horn has been extensively used. They can also malfunction due to material fatigue, but this happens mostly in older cars.
The most common place for the relay is the fuse box or near it.
Diagnostics is done with a multimeter or tester. Simply pull the car horn relay out and check the embedded connections to the relay. If there’s power input to the car horn relay, then you should probably replace it.
Replacement is simple, pull out the old one and push in the new relay.
B. No sound but click sound
i. Main reason for this is either a faulty car horn or weak power supply.
ii. Clicking sound appears when the membrane or the moving mechanism inside the car horn gets stuck.
iii. Reason for this is mostly filth and dirt getting inside and blocking the membrane from moving.
iv. Solution to this problem is either replacement or adjusting the car horn. More about car horn adjustment lower in the article.
v. Weak power supply means primarily checking out the car horn switch and the connection between the steering wheel and indicator stalk. Besides that, you can inspect the horn connector and wiring.
C. Weak sound
i. If you press the car horn switch and you get a weak sound, then you’ll probably have to adjust or replace the car horn completely.
ii. So, before replacing, first try adjusting.
Procedure to adjust:
i. Find the adjusting screw:
It will look like a small bulge on the back side of the horn, usually on the opposite side of the connector. You’ll easily recognize it by the plastic or rubber resin covering it.
ii. Remove the plastic or rubber resin that’s covering the screw:
You can use a screwdriver, scalpel or knife to pick the resin out. It’s tough to get out, so have some patience. You’’ll see a screw head emerging. Try picking out as much as possible so you can properly insert the screw driver.
iii. Connect power output to the car horn:
Start turning the adjustment screw left or right. If the horn membrane is stuck, then you should turn the screw from full left to full right at least once.
If the problem is adjustment, a sound should appear once you’ve turned the screw.
Rotate the screw in any direction where the sound gets better and clearer.
D. Continuous sound
Main reason for this is will be:
i. Stuck or loose car horn switch:
As mentioned, horn switches endure significant pressure while using it. Horn switches are held back by springs which may lose strength overtime or break due to material fatigue. Loose parts or weak springs that can’t hold the switch in place can cause an accidental connection and activate the car horn.
Troubleshooting procedure:
This is solved by removing the horn switch and replacing the springs or broken parts.
ii. Loose-broken connector on the indicator stalk:
Regarding the indicator stalk problem: the copper contact on the stalk can break off, accidentally connect to the connector ring on the steering wheel and the horn will start honking without control.
If this happens the solution is replacing the indicator stalk. This is a costly repair since the stalks are not cheap. But on most cars, indicator stalks are made from two parts so maybe you’ll have to change just one part making this mishap a bit less expensive.
Replacement procedure is complicated. In short, for most cars, it goes like this:
You must take off the steering wheel in order to gain access to the indicator stalk. After that you must take off the plastic trimming around the wheel. Then you must disconnect the stalk, unscrew it of the steering column and take it off.
Returning goes in reverse procedure.
Pretty complicated job and I wouldn’t advise it unless you have at least some experience around cars.