I have a 1990 E350 7.3 Diesel. The horn did not work when I bought the Van. I finally got around to troubleshooting it (after a close call on the hi-way!), and found the connector in the steering wheel loose. I plugged it in and the horn honked........ until I turned the ignition on!

I checked the fuse (#13, found by trial and error because I do not have the owners manual) and it was good. The wires in the steering wheel that activate the horn are Yellow, and a Black ground. I located the horn relay which has three wires going to it. Blue, Yellow/Blue and Yellow/Green. The Yellow/Green has 12 volts going to it, and the Wires at the Horns are Blue. I also installed a radio shack relay I had lying around with the same results... horn honks only with the ignition off.

Any diagrams, info, or suggestions would be much appreciated!

My only theory at this point is that one of the + ignition wires is shorted to the horn circuit in the steering wheel causing it to not create a ground to activate the relay... but this still doesn't make any sense because then the ignition fuse should blow if the + was grounded...?????

Thanks in advance.

 

sounds like some one has messed with your wires
almost has to be a problem in the column
time to drop the column and check the wires for damage

 

mgh,

thanks for the input... I started ripping into the column and realized the harnass going into the steering column is removed from the steering wheel side. I dug in further and pulled the wheel off. Once inside, after poking around for a while with the tester, I realized why the horn was working with the ingition off...

the lug that extends to lock the steering when the key is turned to the off position was providing ground to the steering wheel, thus allowing the horn to work. As soon as the key was turned to the on position the lug retracted and the ground was lost...

So I had to figure out what was supposed to provide the wheel with ground. After some more poking around I made the determination that the small plastic ring in the center with a spring loded lug was most likley the culperate. There was only a metal lug on one side, so I figure the lug for the other side of the ring was broken and missing. I shoved a small finishing nail into the other side and cut it approximately the same length as the other, snapped it in place and jumpered the yellow (horn) wire to it and viola.. honk honk!

Horn fixed. Cruse control fixed. I don't know how long the nail will hold, but the fit was prety snug.

Regardless, I will be on the lookout for the electronics unit / harness for the inside of the wheel next time I am at the junk yard.

 

junk yard may have a good one
a lot of the column stuf is still available from ford
dont always want to pay there price for it