Where is my ground suppose to be for my blower motor on my 1992 ford explorer it didnt work so I grounded it right behind the relay .now it just runs on high constantly even if I turn the switch on low medium or off. did I bypass something or what I like having heat and air but I would also like to turn it on low or medium or off to

Like all electronic devices, a blower motor must have power and ground in order to function. A blower motor that continues to operate when the switch is turned off still has both power and ground present when it shouldn't. Assuming this vehicle has the manual HVAC system (rather than automatic), the blower motor should be disabled by interrupting the power supply circuit to the blower. The ground side of the blower circuit will always have a ground path through the function selector switch assembly. Power is supplied to the blower motor using a blower relay. Relays have a "control side" which also require both power and ground as well as an "output side" which has power and a path to whatever component it is that the relay operates. On this vehicle the control side of the blower relay is always grounded and the power side is only energized when the function selector switch assembly is moved away from the "OFF" position. A short-to-power in this circuit within the function selector switch assembly could provide power at all times and cause the blower to never turn off. Alternatively if we assume the control side is working normally and turning off when it should, the output side of the relay should never provide power to the component. That is unless the contacts within the relay have a short-to-power condition in which case the blower would receive power at all times. To summarize, I would suspect either the function selector switch assembly is internally shorted or the blower relay is stuck in the "ON" position. You can read more here: https://www.yourmechanic.com/article/how-to-buy-a-good-quality-heater-blower-motor

check fuse first
then scan PCM , oops you didnt and the BCM does run this stuff.
so not scanning it , you miss all those FACTS.

the blower is dead. (aka , not spinning , or silent)
on all cars made the answer is the same.
blown fuse, fuse marked BLower, is blown. LOL.
controls not turning it on, controls failure.
blower bad. (motor) hot wire it in place to test)
wires to any of the above.
or the resistor block bad, (if it works on high but not low)
i have the schmematic in hand.

the HVAC relay pulls in by command of the BCM
the relay then sends 12vdc power to the blower via fuse 41
the blower is now hot full time.
the blower then needs a ground to spin (run)
on high, the ground G601 via the speed knob,switch makes that ground connection, so if the fan dont spin and say the fan is ok
then the relay is not closing or the fuse 41 is blown. (why not look at the fuse first for all electric fails)
the BCM sees you, turn fan on, (heat or cold)
and closes this relay, on the left.
if the relay does not close, (and coil is ok inside)
the the BCM didnt see those HVAC requests.
use a scan tool and look for BCM errors..>??????

There is no relay, according to my info. At the blower motor, green wire is voltage, fuse protected, goes hot with key on. Black wire is ground. The blower speed control switch is part of ground circuit. There are resistors for the lower speeds. Hi speed doesn't use a resistor. If you have good voltage and ground at blower motor and no blower action, suspect the blower motor. Any motor that uses brushes, sometimes you can tap on suspect motor, and it will run intermittently. Sign of bad brushes.
You may be able to use jumper wires to blower motor connector for voltage and ground, from the battery, just to see if blower motor will run? If it won't run, suspect blower motor. If you use jumpers, use an inline fuse, just in case.

I had the same issue and replaced the resistor and still had the issue, found out it was the ground to the blower motor relay! cleaned the ground and hooked it back up, works like new!

Aux blower motor relay , did you check that . Or Aux blower motor resistor assembly . Do you know what a wiring diagram is ? Always view one to see all componets , power feeds , connectors etc... So testing with a DMM - digital multi-meter is easier . Free wiring diagrams here http://www.bbbind.com/free_tsb.html
Enter vehicle info. year , make , model an engine ! Under system click on HVAC ,then under subsystem HVAC controls will pop up . Click the search button ,then click the second blue link . First diagram on the right side you will see Aux blower motor electrical circuit . Check B+ voltage an ground . Scroll down to # 6

You need a blower motor resistor. 1986-1992 Oldsmobile Cutlass Ciera Blower Motor Resistor - 4-Seasons
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Part #: FS20072
Mfr #: 20072

There is a relay and a fuse for the blower. Also, check the motor local ground for clean, tight connection. Last, try applying +12 volt power directly to the motor connection to see if it will run.

Check the grounding of the blower motor it's self. Gm had a small issue with the blower motor loosing it's ground. Run a test ground wire from the battery to the blower motor. If this doesn't help, replace motor.

pull blower motor for vehicle run a wire to positive connection and ground wire to the ground place other end of the positive wire to the battery if doesnt kick on then replace with new blower. if comes on fuse is good or check for broken wire if these two dont work or short in wireing.

If the blower is totaly not working it could be a bad motor or a loss of power (or ground) to the motor. There is a blower motor relay on the power distribution box on the right innner fender. There may be a fuse for the heater circuit, also. Power also goes through a blower motor resister that controls blower speeds. If any one of these are bad it will (can) cause the blower motor to not work. I would first check all your fuses. If you have the ability to check for power continuity (with a test light or multimeter) I would check to see if the motor is even getting power. It is also possible that your heater control switch is not sending power to the relay. Electrical can be hard to track sometimes. Good Luck.