Hey folks, I could use some help diagnosing some horn issues on my 1990 F-150.

Long story short, there's a yellow and a blue wire in the turn signal switch that control the horn. Bridging those two contacts with a screwdriver should sound the horn, but in my case it doesn't. If I bridge the yellow contact to the steering column the horn does sound, which leads me to believe that my blue wire is not reaching ground.

From everything I've seen, there should be a jumper for that blue wire that connects it to ground but I can't find it for the life of me. I've looked at every diagram I can find online and just can't find where that connection to ground happens. I could just ground the blue wire to the steering column somehow, but I'm trying to avoid that and do things the "right" way. Any help would be much appreciated.

 

welcome to FTE,your help should be around later so just hang tight for a bit

 

Does your truck have cruise control?

 

I don't know, unfortunately. When I bought the truck it had a moderately damaged steering wheel that didn't have cruise control buttons on it, but I don't know if the truck maybe has them from the factory and the wheel was replaced. It's the XLT Lariat and has other upgrades (AC, cassette player, power windows, etc) so it seems plausible that it would have cruise control. Where would the horn relay be in that case?

 

Is there a cruise control servo on the driver's side inner fender?
What kind of damage does the steering wheel have?
On a cruise control equipped truck, the horn relay is behind and to the right of the glove box.

 

Not that I can find, but I could be missing it. I did eventually figure this out - it turns out there's nothing wrong with my horn relay or wiring, the issue was in the new steering wheel hub from Grant (the second one I've had issues with now). What I ended up doing was adding some solder between the inner ring of the hub and the hub itself, basically grounding the inner ring to the hub, which solved the problem.

To answer my original question for others that come by this, you're correct that the horn relay is to the right of the glovebox on the A pillar. I popped out the glovebox door and there's a clip holding the relay to the inside of the pillar.

Thanks for the help!

 

Glad you got it. So it's a Grant steering wheel or just the hub?

 

The whole kit, wheel plus horn kit. I have one that came on my 66 mustang too and that one was also a pain