Heater Blower Motor Wiring

Need help with the wiring of a stock blower motor for a 74 cj5. I have 2 wires, orange and black, and originally i thought that the haynes manual said black was the power and orange was the ground. Strange I know. That had to be the only reason I did it that way. Unfortunently I am in the middle of moving and after taking into a shop to get some gauge work done, the mechanic used my ground wire off of the toggle switch to ground the gauge and left the toggle switch un-grounded. I didn't know this as I turned on the heater to clear my windows and found the light on the new (broken) fuel gauge came on. Turned on the headlights and it went out. Thought that the original issue where they got the gauge to work then turned on the lights and the gauge went to full and kept going had caused something to short the gauge light out. It wasn't until after a while when I noticed my windows weren't getting clear that I felt to see if the heater was on and found it wasn't. I turned off the switch and the light on the gauge went out. So I am thinking that my Blower motor is wired incorrectly and the power went through the switch, blower motor, to the ground wire of the light and that's why it turned on. (Ground for blower motor and the ground for the toggle switch, now the ground for the light, are at the same location.)

PS anyone put a painless wiring harness into their rig and find that they had to isolate the fuse box from the fire wall to prevent grounds, or have to run independent wires from their senders to independent gauges, bypassing the harness altogether in order to get them to work? Buddy of mine had to on his 74 and just seeing if anyone else has run into the issue.

PPS I HATE ELECTRICAL WORK

 

I'm in the middle of completely rewiring my 74.
One circuit at a time.
I am interpreting the schematic as saying that the two wires to the motor are for high and low speeds and the motor grounds through the case.
Power goes to the switch and one of the wires hooks to the low speed position and the other wire hooks to the high speed position.

Run a separate ground wire from the blower motor housing/case to the battery negative. These old jeeps relied heavily on chassis and housing grounding and now, years later, all these joints and connectins have either loosened and or rusted to the point of intermittent or non-existent current pathways.

 

Thanks. I woulda pulled out my Haynes manual to check this, but it's on a truck headed for the east coast.