Blower fuse keeps blowing
To start of I am an electronics technician and I would certainly be able track this issue down if I pulled all the wires out of the wiring harness which would be way time consuming.
Or if the schematics online were any good would help as well.
I am hoping someone may have run across this issue and can give me an easy fix.
Replacing the fuse used to make the blower work for a few days but now it blows instantly.
Here is what I have done.
1. Pulled the motor and tested it with 12V. Runs well with about 5 amp draw.
2. Thinking the brushes on the motor might be intermittent I plugged the motor back in but did not put it back into the firewall. Fuse blew instantly.
3. Unplugged the motor - Fuse still blew instantly?? Not sure why that would happen.
4. Measured across the wiring harness right at the motor connector 5.7 Ohms. with the fuse removed and no motor (no load) I would expect infinite Ohms per what the poor schematics shows.
5. Disconnected the connector from the resistor pack Infinite Ohms at the motor connector, but fuse still blows. This tells me the short is beyond the resistor pack.
6. I measured resistance from ground to each wire on the resistor pack resistance infinite except the gray/blk wire which was 3.2 Ohms to ground, so short is on that wire or futher in the circuit.

Schematic says just "To function switch" with no other details as to the function switch or how this function switch could be shorted to ground. I will try to dig into the dashboard in the next couple days if no one has an answer, but I dread it. I have little time before dark once I get home from work to get much done each night.

Try unplugging the A/C control switch & seeing if the fuse still blows this could let you know if the wiring is the problem of if it might be the switch some times those short out too.