Hi guys. I have not asked for help on here in a long time. I have a 1999 dodge ram 2500 diesel. This has been a complete rebuild, every nut and bolt, frame off restoration. I have had all kinds of issues with the wiring on this thing. I have been solving them as I put it back together. This horn and cruise issue has me beat, at least for the time I've put into it. First off the horn issue, I am getting no power through the harness at the horns, should be the green wire. The black wire is ground. This sent me to check the fuse, that is good. Then I was reading on here that it could be the clock spring. Yes my air bag light is on as well. I have now removed the clock spring in hopes of finding why there is no power to it. Is the power feed through the Air bag connection under the dash? Or another way? Both Air bag fuses are good. There is no power through the Air bag connector.

 

Download the service manual for your truck from here. Wiring diagrams are in section 8W. Have a look, see what you come up with.

 

I spent alot of time trying to solve a similar problem a couple weeks ago.

If the airbag light is on it means that the computer doesn't see that it's plugged in or functional. But since all those function aren't working it leads me to think that it is a wiring issue like the other guy suggested.

With the battery disconnected and "let capacitors discharge for a few minutes" you can take the airbag module off the wheel using a... 8mm? I think it was a couple 8mm screws on the back. Under the airbag module there is going to be one singular wire that plugs into the airbag and then also a 2 pin connector that goes to the airbag. Unplug the airbag one so you don't get any pop off. Reconnect the battery and then manually ground the singular wire to somewhere on the body and listen for the horn. Basically all this wire does is go through the horn pressure switch and then grounds itself out to the bolts that attack it to the column.

If that doesn't work under the wheel there should be a flat connector that goes into the clock spring. Idk about your model but find which of those wires goes through the clockspring and into the wheel to the one you just grounded. See if there's continuity. Then try grounding that wire to see if things work there. Basically this is just going to be backtracking until you find something that does work.

 

Did you have the steering wheel off? I'd check, or even replace the clockspring in the steering column. It sounds like you have a plug that isn't fully seated.