blower motor

I have a 99 cherokee I just replaced the blower motor, but now when I try to turn it on it only works on high. What could be the problem.

I would test the switch and check if there's a blower motor resistor in the circuit. If the resistor goes bad the blower will only operate in some settings.

I already checked the resistor and that wasn't it. Is there anything else it could be.

I would test the switch and check if there's a blower motor resistor in the circuit. If the resistor goes bad the blower will only operate in some settings.
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The resistor provides a ground path for the blower. Sounds like you may have pinched the blower wires when you replaced it and it's grounding out directly.