Welcome back:
Then either we have an electrical issue or the motor needs to be warm before it will start working. I am going to provide directions for testing for power. However, I just remembered a situation very similar to this. The problem was the fuse under the dash. The fuse box had overheated and the fuse wouldn't make contact until the interior began to warm up. So, when it isn't working, wiggle the fuse in the fuse box under the dash to see if it starts.
Now, it that makes no difference, take a look at the attached picture. I will try to explain how to test for power.
The first place to start is the green wire at the motor. When the switch is in the high setting, you should have 12v. When you select different speeds, the voltage will be reduced.
If there is no power, move back to the blower motor resister. Is there power letters A (lt blue) and C (tan) when the speed is in the select positions as indicated?
If there is no power there, then confirm there is power to the switch via the yellow / brown wire.
Here are a few links to help with the process:
https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester
https://www.2carpros.com/articles/how-to-use-a-voltmeter
https://www.2carpros.com/articles/how-to-check-wiring
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Basically, if there is power to the switch but it doesn't go to the resister, the switch is bad. When you place it on high, there should be power the green wire at the motor. If there is and it doesn't run, replace the motor. As far as the resister, other than corrosion causing an issue, since it works on all speeds when it runs, the resister is good.
Do this and let me know what you find. Also, if you have questions or need help, let me know.
Joe
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Monday, October 14th, 2019 AT 5:56 PM
