Good name. It made me click. That and the HDX part.
So Iím in NOLA and own a 2001 HDX 3126b. AND I just bought a power probe from Amazon last week and am learning how to use it.
I will send some electrical diagrams for my bus that should be similar to yours. You can call Thomas in High Point, give them your VIN for more accurate drawings.
Two years ago I had the exact same symptoms. I had screwed up my interlock system. While doing the ol screwdriver jump the starter relay thing, my bus went dead like yours. After much head scratching I hired a professional. I had blown the fuse inline that powers the ECU.
If you google 3126 ecu fuse, you will see rv forums full of ppl looking for this fuse. We never found it either.
My guy ran a wire from the ignition switch the back to the proper pin on ECU. He also included a 10 amp inline fuse. Clackaty clack she started right up.
So then I had to run a new ignition wire front to back to power the rear box. If I remember correctly, HDXs need to have the switch on in front before you can hold the engine door button and press start in the rear.
The diagrams Iím sending have pics of the wiring pins, and the box in the back. You could probe the input pin with a power probe and power it up. Have someone look to see if your dash initiates,or just listen for the ABS system to make its funny noises. If so thatís your problem. Either find the fuse or run a new wire.
If you run a new wire, you have bypassed the neutral safety switch on the tranny. So if you find the fuse let me know where it is.
Or......it could be something completely different!
This is where I always say I AM NOT A MECHANIC OR AN ELECTRICIAN. I have seen a few things in the last 2.5 years and I relay what Iíve seen.