I have pieced together a factory cruise control system from a couple of different model year trucks. I thought everything would work together, but it doesn't.

The truck is an '83, the steering column is from a '90, and the cruise amp and servo is from an '86. It all connected together, but it immediately pops a fuse, I think it's circuit 15, the same as the 4X4 indicator light.
I looked at some wiring diagrams to try and figure out if some of the connectors changed the wiring layout between years.

Does anyone know which pieces or years do or do not work together? Or if there is simply a couple of wires that need to be swapped around to make this work?

 

How did you get all the wiring to plug in and work? I am pretty sure the 90 used a speed sensor in the rearend, the 86 used a sensor in the speedo cable. Do you have the diagrams and can post them up? I only have the 86 cruise diagram, I don't have the 90. How did you mate the 90 ignition switch to the 83 wiring? Did you use the 83 switch on the 90 column?

It seems if you have gotten this far, you would have seen where the problem could be. As in "I had to cut and modify this plug to fit". I would think that might be where the problem is.

 

Yes, I think I'm close to having it work but I just can't seem to see where the problem is.
The ignition switch wiring harness on the '83 just plugged right into the switch on the '90 column. Everything else works: starter, signals, horn.
The '86 had a speedo cable driven signal generator that I hooked up with everything else.

I didn't have to hack any wiring or make any splices. I just installed everything and plugged it all together. I just thought it would be plug and play.

 

Something came to mind when I read your reply. Did the 83 have cruise? I am assuming the 90 had cruise, you are probably using the buttons on it's steering wheel.

The reason I am asking, trucks without cruise did not use a horn relay. They ran power from the fuse box up a wire to one of the brush contacts in the column, to the horn button, back out of the horn button, back through the other brush, and then down the column and directly to the horn. All the current that it takes to drive the horn went through the horn button.

When a truck had cruise, the did it differently. They had a relay mounted I believe on the driver's side above the kick panel area. The power for the horn left the fuse box, went through the relay, and out to the horn. To activate the horn relay, they ran a single wire from the relay, up the column through the brush contact, through the horn button, and then to a ground in the column. The relay has power on it all the time, to make it work they ground the other side of the coil at the steering wheel, and it activates the relay.

If you happen to take the power wire from the old non-cruise system that comes from the fuse box, and hook it to the horn wire for the cruise system in the 90 column, it may be grounding out the power wire and blowing the fuse.

 

Thanks, that seems like a logical circuit to track down and check out.
The horn relay I have came from the '86 donor and is mounted on the side of the cruise amp, which is under the dash near the gas pedal. The horn works normally.