Simple Headlight Trouble shooting for gen II Prius

In this simple trouble shooting procedure we will be listening for the click sound of relay H-LP and relay DIM turning on.
Raise hood remove relay/fuse cover on driverside fuse pannel (where relays H-LP and DIM are located). With drivers side window down turn on headlights..Did you hear H-LP relay click GREAT!....Relay H-LP is now supplying power to the DIM relays activation coil and contacts.
If relay did not click check 40amp fuse link labled 40A-HEAD viewable thru clear plastic strip on the very left side of pannel. (It is highly unlikely this fuse could EVER be blown)
Now with headlight switch still turned on switch to high beams did you hear DIM relay click on. If not Relay H-LP is bad and not providing power to the DIM relay (energizing coil). If you can hear DIM relay clicking on and off while toggling from low and high beams and hi beams back to low beams and you have no headlight illumination your DIM relay contacts are shot/burnt/gone.. DIM relay will have to be replaced. It unplugs from fuse pannel (difficultly).
If only low beams or only high beams work DIM relay will still need to be replaced..

If you cannot get the H-LP relay to click you have a dead battery or a locked up body ecu/computer or a broken headlight switch.

The four headlight filiments (left high and low and right high and low beams) are seperately fused each with 10 amp fuses located next to the H-LP and DIM relays.
The chances that all four of these fuses or even two of them blowing are absolutely impossible, unless you've just been in a wreck or you have just botched an HID installation or you have just altered/modified the headlight wiring in some extreme way...

And the chance of the 40amp HEAD fuse link blowing ... IMPOSSIBLE only if you have just totalled the car in a horrible accident. MAYBE !!!!

If you must trouble shoot beyond this remove the four 10 amp filament fuses located next to H-LP and DIM relays. Then take a small piece of wire 6 to 10 long and capable of caring 5 or 6 amps. Meter probe lead would be perfect.(with everything turned off).. jumper from jump start terminal (go right to the copper nut and bolt) under red cover to all of the removed fuse connections (one at a time) four of those connections will light each headlight beam. The other four connections will only back feed 12 volts to the DIM relay contacts (no problem). This will have tested the headlights and the headlight wiring leaving only the relays as the source of any problem. But again if the high to low beam relay (DIM) can be heard clicking on or off then H-LP relay is good and supplying power to the DIM relay activation coil. Leaving only the DIM relay for replacement.. Hope this helps all future problems with worn out DIM relay.