Q: The headlights wont shut off and the horn keep honking when I turn them on.

asked by on

Lately I've been having a problem with the fuse that powers the dash lights and the tail lights. I have to replace the fuse every two weeks. I was driving up the road recently and that fuse went out and right after that the horn started honking. I pulled over to look at it I noticed my headlights were on. So I went to turn them off and when I did the horn shut off but the headlights didn't. After I did that the horn wasn't honking anymore so I drove home. When I got there and parked and shut the car and the headlights off, the headlights were still on. I pulled the horn relay and the light relay and they both shut off. I also pulled off the battery cables. What could have caused this, and how can I fix it? Thank you for your time.

My car has 210357 miles.
My car has an automatic transmission.

It sounds like you have a rubbed through wiring harness or two. All the components you mentioned are switched on the ground side. That means if there is a short to ground on the switch side before the relay, then the light will turn on. This would lead me to think that there is a rubbed through harness in the steering column. This will not blow a fuse though.

The light or horn will simply turn on without you moving the switch. The fuse for the taillights and dash lights is a different concern. A short to ground on the positive side, after the relay will blow a fuse. It will only blow the fuse when it is switched on. This could mean a short in any positive wire in the taillight circuit. There are a lot. Every switch that illuminates when you turn your parking lights on could be shorted. Any taillight or parking light circuit, too.

Here are some tips. There is only one way to find this type of problem - it will have to be visually traced. Follow the harnesses with your eyes and look for damage. Use the clues that the car is giving you to narrow your search. The wires will need to repaired after the problem is found. If you need help having this diagnosed and repaired, a certified technician from YourMechanic can inspect your electrical system and let you know what fixes need to be performed.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. The headlights wont shut off and the horn keep honking when I turn them on.

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: My car horn goes off randomly

There are a few things along the horn circuit that may cause this type of concern. The horn switch inside the wheel may be shorted and will trip the circuit to sound the horn. There is also a relay in...

Q: Should I Replace My Headlight Bulbs With LED Bulbs

The best answer to this will depend on what your intentions are with respect to your lights. The standard headlights on vehicles come in many forms including halogen, Xenon HID, or LED (light emitting diode). There are different types of...

Q: Transmission staying in 3rd gear only and not shifting.

Hi there. The transmission could have an issue with the shift solenoids. Check the wiring harness to the transmission case and make sure that it is plugged in. 3rd gear is the only forward gear in a 4L60E transmission that...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.