Right, to get to the relays you remove the blower intake housing(easy) -
but the only reason to access the relays - would be to replace or test them.
If you want to switch the fan with the PCM grounding wire - the easiest place
is at the PCM connection - you can find the grounding wire for the 'fan on', and
the 'high speed' - in your manual. Then all you do is connect a wire from the
grounding signal wire to a manual switch that connects to a ground.
Another way to manually control the fan motor is to run a + wire off the
battery jumper post(driver side) to a relay then connect it to the fan power wire(at the fan motor)- the relay will need a + and - connection, and can
be switched by either.
I have a GEN-I - which has a longer fan circuit which can hardly handle the amp
draw of the updated 99 fan - so I completely re-did the high speed circuit,
Now my high speed circuit runs directly thru a 10g wire, straight from the
battery jumper post - and is switched by an added relay next to the fan motor
by the former power wire. I also added a manual high speed switch - so
I can turn the high speed on anytime - even when the car is turned off.