Possible short in horn switch, how do I access it?

Hello,

If you've recently replaced your indicator switch and light switch with a second-hand one and now your horn is sounding continuously when you connect the battery, there could be a few potential reasons for this issue:

1. Wiring Issue: Double-check the wiring connections for the indicator switch and light switch. Ensure that all wires are correctly connected to their respective terminals. A loose or incorrect connection could be causing a short circuit, which might trigger the horn.
2. Faulty Switch: The second-hand switch you obtained might be faulty or damaged. It's possible that there's an internal issue within the switch itself, causing it to send a constant signal to the horn.
3. Short Circuit: It's possible that during the installation process, a wire got pinched or damaged, creating a short circuit. This could lead to continuous power being supplied to the horn circuit.
4. Grounding Issue: Check the grounding of the switches and the horn. Poor grounding can lead to erratic behavior in electrical systems.
5. Compatibility: Ensure that the second-hand switch is compatible with your vehicle's make and model. Different vehicles might have variations in wiring and electrical systems.

Here are a few steps you can take to troubleshoot and address the issue:

1. Disconnect Battery: Disconnect the battery to stop the continuous horn sound and prevent any further electrical issues.
2. Inspect Wiring: Carefully inspect the wiring connections for any signs of damage, loose connections, or incorrect connections. Make sure that each wire is connected to the correct terminal on the switches.
3. Check Switch Functionality: Test the second-hand switch separately before connecting it to your vehicle. Verify that it functions correctly and doesn't cause any issues when operated.
4. Test Horn Circuit: Test the horn circuit by disconnecting the wires from the horn itself. If the horn stops sounding, then the issue is likely related to the wiring or the switch. If the horn continues to sound, the problem might be in the horn relay or elsewhere in the electrical system.
5. Professional Help: If you're unable to identify and resolve the issue, consider seeking assistance from a professional mechanic or an automotive electrician. They have the expertise to diagnose and fix electrical problems effectively.

It's important to address electrical issues promptly to avoid potential damage to your vehicle's electrical system and ensure safe operation.

possible clock spring problem or wiring problem with the switchs/circuit you would need to open up column -remove steering wheel and check them

Could be a wiring problem or the clockspring in the steering column.
You would need to pull the steering wheel and test the circuits.

Most vehicles have a horn relay, which should be in a fuse box under the hood. Toyota is usually pretty good at identifying the various relays and fuses in the fuse box. If your original horn was shorted, it very well could have welded the contacts in the horn relay together. Also an aftermarket horn could be drawing more amperage than an original equipment unit, causing the fuse to burn. This last statement is purely conjecture.

By tracing the horn and light switch, did you find the short? If the horn is shorted, then it should only run the battery down if the horn switch is made. Or the horn is pressed. So I would suggest the light switch is going to be where the problem is.

possible horn switch, short or clock spring

A fuse always blows for a reason. The reason your fuse must have blown was because of a short to ground in the horn switch. That means the power side of the horn switch is currently touching ground or metal or that the switch is bad on the inside. The more remote possiblity is that you have a short somewhere in the wiring harness. It is always typical for a component to go bad before a harness.

Here are some notes directly from chrysler, let me know if you need any clarification:

Testing and Inspection Notes WARNING: ON VEHICLES EQUIPPED WITH AIR-BAGS, REFER TO AIRBAGS AND SEAT BELTS/AIRBAGS BEFORE ATTEMPTING STEERING WHEEL, STEERING COLUMN, OR INSTRUMENT PANEL COMPONENT DIAGNOSIS OR SERVICE. FAILURE TO TAKE THE PROPER PRECAUTIONS COULD RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL INJURY.

1. Disconnect and isolate the battery negative cable. Remove the lower steering column cover/knee blocker. Check for continuity between the metal steering column jacket and a good ground. There should be continuity If OK, go to Step 2. If not OK, refer to Steering and Suspension/Steering Column and check for proper installation of the steering column mounting nuts.
2. Remove the driver's airbag module. Unplug the horn switch wire connector. Remove the horn relay from the Power Distribution Center (PDC) . Check for continuity between the steering column half of the horn switch feed wire connector and a good ground. There should be no continuity If OK, go to Step 3. If not OK, repair the short circuit as required.
3. Check for continuity between the steering column half of the horn switch feed wire connector and the horn relay control circuit cavity for the horn relay in the PDC. There should be continuity If OK, go to Step 4. If not OK, repair the open circuit as required.
4. Check for continuity between the horn switch feed wire and the horn switch ground wire on the airbag module. There should be no continuity If OK, go to Step 5. If not OK, replace the faulty horn switch.
5. Depress the center of the airbag module cover and check for continuity between the horn switch feed wire and the horn switch ground wire on the airbag module. There should be continuity If not OK, replace the faulty horn switch.

You possibly have a bad switch. The one in the driver's door has 6 switches on it. Unplug it to see it your problems stop with the door. Your horn relay is shorted, replace it to stop the honking. Could also be the switch plate is in the short position. Unplug your horn, under front driver's side. Pull black splash guard behind/under front driver's bumper to access it. Unplug wire from horn. Relay should be under driver's side dash. Take off knee guard screws and you should see it in there. Unplug/replace it.

Hi,

As in most electrical problems, it would be required to do a bit of tracing/diagnosis to determine which is at fault. Most automotive horn system works on the same basic design. A switch in the steering wheel that energizes the horn relay that in turn powers the horn(s). A self activating horn could be caused by:
1: intermittent short in the steering wheel horn button;
2. intermittent shorting out horn relay;
3. intermittent short in the wiring.

Basing on the above possibilities, diagnostic/corrective action would involve:
a. tapping on the steering wheel (not the horn button) to see if jarring it would activate the horn, if yes then the problem is with the horn switch and often cleaning the inside/contact points of the switch should be corrective;
b. tapping the horn relay with the handle of a screwdriver to determine if jarring it would activate the horn, if yes then the problem is with the horn relay which of course would need replacement;
c. the wiring would be a bit more complicated if not time consuming. It would be necessary to wiggle the wires coming from the steering wheel/column to the main harness, to the fuse/relay bank finally to the horn to check at which point the trouble would resurface. Taping any exposed/bare/scraped wire would be corrective. It should be noted that the steering horn switch often would be "to ground" meaning the horn switch is switching the horn relay by providing the negative path, the relay is constantly supplied with B+12.

There are some instances that the horn could also activated by an alarm system.

Hope this be of initial help/idea. Pls post back how things turned up or should you need additional information.

Good luck and kind regards.

Thank you for using FixYa.

Hi,

There would only be three (3) possibilities for a continuous blowing of horn:
1. defective/shorted horn relay ( very unlikely);
2. defective/shorted horn switch (very likely); and/or
3. shorted/grounded wiring (likely).

The horn switch is the contact switch normally embedded into the steering wheel.

Hope this be of initial help/idea. Pls post back how things turned up or should you need additional information.

Good luck and kind regards.

Thank you for using FixYa.