Originally Posted by Arthur Dalton

Behind the brake booster is the 3 wire plug .

With key ON , you want 12v from red to blk..then you want a variable voltage [ from 2-9 aprox] from the yellow to blk, depending on where the fan speed selector is at. That is the trigger voltage for the regulator and you have to check that first b/c many guys change the regulator at great cost only to find out they simply had no trig V at the yellow wire..NO Trigger V. = No fan. And no trigger can be a simple CC panel fuse or bad ign sw.

If you have those 3 test as verified at the connector/plug, then you have to go down to blower motor..the simple test there is to ground the blue wire with a jumper wire to ground..if you then get High Fan, the problem is the Regulator [ providing you know you have Variable trigger at yellow wire at regulator.]

A word of caution for the fuse link that you verified.
The best test for that is to jumper it with a fused jumper wire b/c they can test fine w/DMM until the fan circuit puts a load on the fuse ..it then opens up...so a quick jumper there may save you a lot of false diagnostics..........