I've been testing the wrong @#$%@#$ relay!
I hate when that happens - & it does happen to everyone.
I do this kind of trouble shooting every day, so I will try to walk you thru it.
It is not your blower motor resistor, so don't replace that.
If you unplug your (newly located) high speed fan relay & put a jumper wire across the 2 large wires (red to purple) your fan should turn on high speed. This is the output side of the relay & the terminals we are looking at are #87 & 30.
If it does not turn on, you have a power supply problem from the junction block thru the fuseable link to the relay. Check for power on that red wire (#87) - should have battery voltage available there.
If it does turn on, you have a control circuit fault - meaning there is no power on the orange wire when the fan speed it turned on high (or you have poor ground). Check the terminal #86 (orange wire) at the relay for battery voltage when the switch is turned to high speed.
Hopefully this gets you started in the right direction.