PLEASE, PLEASE help- 1983 E350 Ford 460 RV

Sounds like you should have a mechanic try to fix the cruise control and horn. If you are not careful, you might make it worse than it is. In the long run, you would be ahead to have a mechanic fix it. I don't mean an RV guy, an automobile or truck mechanic.

Look for a junkyard van or pickup with tilt steering that has the same center. Chances are that you might find not broken parts on one pickup or another.

Your local Ford dealer might have them too, and no time wasted searching around for them.

Fred.

Cruise control have a sensor mounted close to drive shaft. check for corrosion.other wise the servo that regulates the speed could be defective.
Had a similar issue, ended up replacing with an aftermarket.
The horn has a relay not a module. replace the relay and you should be set to go. And if not take it to the mechanic

So your RV is bit older then what I'm used to working on, but I can give my thoughts.

Horn. You say you have power to the tabs. Have you tried to ground them manually? some horns are ground interupted and some can be positive interrupted. by touching the tabs together you should have a horn go off.

If this doesn't work. its one of 2 things. the ground wire is broke somewhere in the harness. and or you have a horn relay that is not operational.

A relay on your unit would be under the dash and or in a power distribution box inside the engine compartment. See if you can obtain a FSM online or Factory service manual. it will tell you everything you ever wanted to know about the drivetrain.

Very uncommon would be a horn that stopped working you can use leads to power off battery and touch to ground that would let you know the actual horn works and you can work back from there.

On your Cruise. What isn't working?

Typically older cars some have clock springs some do not. if you have buttons on the steering wheel area you might have one. if its a tree stem or the unit that comes from the side that works other functions. those modules are very common for failure. I would start there for electric operation. they fail quite often.

the other thing is the the type of Cruise you have most older vehicles have vacuum assisted cables that operate the TB or carb. check for vacuum.

also cruise usually only works on speeds over 30mph so it can be hard to check in the driveway.

You problably don't have airbags but if you are ever working around bags you need to know how to disarm them properly or serious injury and damage will occur.

hope this helps a bit.