Write Up: Horn Relay Fix

[Rotary_Rocket_87]

This write up may not apply to all problem related to a non-functional horn. This is merely what it took to fix my problem.

That said here it goes. I will be as decriptive as possible due to the lack of pictures.

Step One: I took a length of wire and jumpered the horns to make sure they were not malfunctioning. All three (one for the security system I assume) worked properly.

Step Two: Remove the Driver's side kick panel. Located here is a black box called the CPU. This controls horn, turn signal and hazard flasher functions. In my T2 it was marked FB05 (my N/A's was marked FB01, not sure what the difference is). Remove the 10mm nut that secures the top of the box. Pull the box off of the stud the nut was on and lift up. You can now pull it into the footwell area for ease of unhooking the three electrical connections. The bottom two connections are for the turn and hazard lights. Disregard these for this fix.

Step Three: Now that the CPU is out take the screw out of the back cover and gently pry the cover off. The plactic can break easily if too much force is applied. Now you are going to want to take the circuit board that is exposed out of the box. I gently pushed on the pins in the connector port, being careful not to bend or break them.

Step Four: The two relays that are soldered on to this board are where the problems mostly occur. In my case a simple cleaning with a quick drying electrical cleaner was all that was nessesary. Simply spray the cleaner on the contacts of the relays. Allow to dry and repeat if nessesary.

NOTE: In other cases the solder connecting the relays to the circuit board is cracked and must be re-soldered. If this is the fix that you need to make, go to www.mazdamark.com and I am sure Mark will help you with instruction.

Five: After taking the required steps for your application, reassemble the CPU and reinstall it. If you are still having problems with the horns keep reading.

Step Six: Remove the centercap of the steering wheel to access the nut secruing the wheel to the steering shaft. Remove the nut with a 22mm socket and remove the steering wheel. I found that wiggling the steering wheel forward and backward is enough to loosen it from the splines. If this doesn't work use a steering wheel puller to remove it. Once the wheel is removed you will see the Turn Signal Cancel and Horn Switch. The springloaded pin is the contact for the horn. On the back of the steering wheel is a metal disc that this pin contacts. Clean these as needed. After they are well cleaned use a thin film of dielectric grease to protect the bare metal. If too much is used dirt will be attracted, causing bad contact again.

Step Seven: Reassemble the steering wheel and give it a try. The relays will make an audible clicking if working. Oh and your horns will work. If you are still experiencing problems you may have to trace wires. I hope this helps a few of us, and Thanks for reading.