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Has the relay been checked? Also, I feel like I answered this question. I may be going nuts. LOL
There are two relays related to the blower motor. I attached a pic of them and their locations. Here is a link that shows how a relay is tested:
Let me know. Also, disconnect the connector at the blower motor and check for power in all speeds.
Here are a few links you may find helpful:
Interestingly, you mentioned the resister is good. And based on symptoms, it does sound good. Most times when one fails, only the high speed will work and nothing else. However, I would still remove and inspect it for damage.
Let me know what you find or if you have other questions.
Thursday, October 24th, 2019 AT 7:34 PM