Obd1 wiring help to 71 Duster
Not exactly sure what you're asking - but here goes.
1) What I did was to simply install the engine and harness. Mounted the PCM (computer) to the rear of the passenger side shelf in the engine compartment.
2) I installed the PDC (fuse panel) on the rear of the drivers side shelf.
3) Find the run wire that connects the Ram ignition switch to the PDC. Then connect the run wire from your ignition switch to the PDC wire. Now you have your switched hot.
I used the Ram battery and alternator cables. The battery cable feeds the PDC, so you have your hot wire connected there.
You may not want to do what I did, but I rewired everything I could through the PDC. If nothing else, it puts most of your fuses under the hood where you can easily get to them instead of having to get down and crawl under the dash to change a fuse.
If you want to install halogen or HID headlights, you can use the relays in the PDC. I also ran my horn through the horn relay in the PDC. Stop, tail, brake and fog lights were routed through the PDC.
I drilled and tapped a hole in the intake manifold to install a water temp sender for the old gauge. Also, I used the old oil pressure sending unit for my old oil pressure gauge.
While I was at it, I removed the old ammeter from the Barracuda and did away with the megasplice under the dash. This may sound kinda complicated, but it's really not. If you have any specific questions or need any further information you can always PM me and I'll get back with you.