i have a 97 grand cherokee and the blower motor would cycle on and off in all speeds. the blower doesn't operate at all now. i've checked the fuses and relay and they seem to be fine. any advice on what and where to start troubleshooting would be appreciated.

Do you have the Automatic Climate Control? If so, there is a module that regulates the blower speed. If not, it will be a big resister panel that usually is mounted in the airbox somewhere.

go to the blower motor and disconnect the electrical connecter turn the fan on high. is there 12V(give or take 0.5v) next lower the fan speed, the voltage should drop accordingly. if the voltage is correct then its your blower motor. Ooor, somtimes you can get it to work again by smacking the motor fairly hard with a blunt object (red neck diag)
if no power to the blower motor... we really need to know if you have eatc(electronic controlled) or standard control at this point,in-order to go any further in the diag process

go to the blower motor and disconnect the electrical connecter turn the fan on high. is there 12V(give or take 0.5v) next lower the fan speed, the voltage should drop accordingly. if the voltage is correct then its your blower motor. Ooor, somtimes you can get it to work again by smacking the motor fairly hard with a blunt object (red neck diag)
if no power to the blower motor... we really need to know if you have eatc(electronic controlled) or standard control at this point,in-order to go any further in the diag process
Actually the blower motor has 12v all the time.The resistor and switch are on the ground side.
Also the " red neck diag" also works great on starters and power window motors.

It has manual control air. After checking voltage and the blower motor I used an alternate ground and the blower now works in all speeds. However while tracing the ground wire for a possible short I noticed a loose and burnt connection(this is located under the glove box and has maybe 8-10 wires plugged in a wiring harness connecter) where the black ground wire connects with a green wire(I assume goes to the switch) this wire gets hot while the fan operates in high speed.Where does the black wire that goes through the firewall go(power distribution center maybe)? I figure it has to be a ground problem because when I grounded it the rear wiper worked for a moment,Any suggestions about where these grounds may be tied together would be appreciated thanks in advance.

your going to have to replace the connector. replace any damaged wires as well. try and find the root cause of the short if you find any evidence that would suggest the original short did not happen inside the connector.

up underneath tucked behind center of the glove compartment, is two white wire harnesses, sheake them it will make it work, loose connections i guess, make mine work, had same problem.

up underneath tucked behind center of the glove compartment, is two white wire harnesses, sheake them it will make it work, loose connections i guess, make mine work, had same problem.

Ditto! I wish I had read your post prior to the past few mornings with ice on my windshield