Yes, double check your diagram, and your reading at the relay.
Are you measuring the correct terminal at the relay?
You should have two hot terminals at the relay: 30 and 86. Do you have a good battery level on both terminals? (The key one is the 30 terminal, which powers the fan. The 14v at the 86 terminal is only to power the coil to turn on/off the relay).
If you suspect the relay could be bad (enough current to blow the fuse also could have welded or burned out the contacts), then swap it with one of the other relays there to see if it fixes it.
As someone else noted, jumpering from 30 to 87 should turn on the fan.
If that doesn't, you can take a wire right from battery to the 87 terminal, to see if that works. If it does, it tells you that power is interrupted somewhere between battery and the relay. If the fan doesn't turn on, you have a problem somewhere from the relay downstream to the fan.
You might need to pull out the power distribution center and have a look at the wires coming into the back of it, to make sure they are OK.
It should be fairly straight forward. You should have continuity from the battery + terminal to one side of the fuse. You should have continuity from the other side of the fuse to the 30 terminal, and from the 87 terminal to the + lead on the fan. The Fan should be grounded on the other side.
Trace those 4 items with a meter and you should find your problem.