My '99 Toyta Tacoma horn does not work

Possibly an errant theft alarm??

Have you checked the horn relay to see if it is working ?

1- The HORN fuse is located in the fuse panel on the driver's side under the engine hood. Of course, if it is "blown" replace with the SAME size or smaller and retest the horn.
2- Verify the horn itself (isolated) using one wire attached to the Main Battery + (POSITIVE) to the spade terminal on the horn. The horn can be accessed after carefully unclipping the fasteners connecting the front grill to the radiator area- just be careful- work slowly. The horn is naturally grounded to the vehicle frame.
3- If the horn sounds with the direct bypass voltage test move to the cab. when you depress the combo horn pad/airbag listen carefully for the relay behind the left under-dash area. If you hear it, then the relay is "closing" but it still may be bad or the voltage from the horn relay is not getting to the horn. I would replace the relay. However, there may still be a wiring problem to the horn.
4- The Horn Relay for the '00 Toyota Tacoma V6 4WD I worked on was BEHIND the cabin fuse panel on the far left driver's side (oh thanks guys). I went to the trouble of pulling down this relay/fuse block- it was not exactly "easy" but I am not a beginner and had the tools and my curiosity and sleuthness prevailed. If the new relay does not fix this issue my next step is to replace the wire from that relay to the horn. Again, not easy but not impossible either. Take you time, use the right tools and materials & check your work. The only other option was mentioned earlier- drop in a new momentary switch (lighted?) into the dash and run a new wire. I would NOT use switched power so it can be used without the vehicle running... I think it is safer. This is a view of the interior panel dropped down. One of the relays can be seen- the grey cube with a empty relay socket just to the right. Why they put these here- is anyone's guess.

There are also relays for the horn. First check would be the connections at the horn then the fuse. If the fuse isn't blown, it's possible that the relay has gone on it. Another item to check would be the wires leading up to the horn it's self. If any of them are frayed and touching bare metal, causing a short circuit, the horn wouldn't work then.

Diagnostic Test Code (DTC) C1244 is a "maufacturer-specific" code used by Toyota for this vehicle. Toyta defines this code simply as "DECELERATION SENSOR CIRCUIT."

Possible causes are:
> Faulty ABS deceleration sensor
> Open or short in deceleration sensor circuit
> Defective wiring harness or connectors

The deceleration sensor for your 2004 Toyota Tacoma is located under the passenger seat.

if it was a fuse problem the horn wouldn`t make a noise.it sounds like the horn contacts that touch when you push on the button are not making proper contact each time.if you remove the horn button and look at the contact spots you may see the problem(uneven contact surfaces).if you move/bend the contact surfaces closer to each other of straighten this may help the problem.you may even have a horn that needs to be replaced as you said when it does work it stutters and not blow.the diaphragm in the horn can dry out and not vibrate like it should.try tapping on the horn when someone tries to blow the horn if it stops or gets louder then the diaphragm is no good.you could also check the connection at the horn itself it may have a bad connection due to corrosion and just need cleaning.

Hi Bob,

That is a really common issue with the tacoma overhead console. Components on the board oxidize and the unit fails. We fix these on a routine basis, have a warranty, and removal instructions; check it out www.autoclockrepair.com. Please let me know if I can help, thanks!

The owners handbook states that it indicates a malfunction of the air bags and advises to take the car to a dealer.
But.. sometimes a dodgy connection can cause this on a lot of cars. Sometimes the connectors located under the seat cause trouble on many. Also, the connection to the steering wheel air bag.

To make sure this isn't a one off, you can disconnect your battery for 15 minutes then reconnect. See if the fault clears.

If it doesn't then there's a fault most likely. Whilst the battery is disconnected, have a check of the seat connections if you can.

If there is an SRS fuse, you can just remove that to disable the airbag system, rather than disconnecting the battery itself. This way you don't loose your radio settings etc.

Rewire your horn from the steering wheel to the horn. Its not difficult, I can't tell you how to take the steering wheel apart but you can get a Haynes Repair Manual. It'll have all you need and more. You can use speaker wire, split it in two. Run one cable from the positive in the battery to the horn switch in the steering wheel. Another from the switch to the horn. You have a short somewhere, to me is easier just to run new wires than to find the short-circuit. Make sure when you run the cables through the firewall you run through a grommet so it does not get damaged by metal. Before anything check your headlight wires that they are not touching the horn.