5KCS Fan Low/Medium Speed

[Steve Sherman]

I think I have lost my low & medium speeds on my radiator fan.  Just
noticed the engine temps climbing higher than usual and the lack of any
fan noise.   Fan is still working in that it will come on after the
ignition is off or if I short out the afterrun terminals.  But when
running, no fan until temp reaches about 65% of the temp gauge (much
higher than before).

I've checked and no blown fuses.  Also thought that it might be some
relays for this, but the diagram on the aux relay panel is useless for
identifying what's what.

Can anyone give me a part # and definite location of the relays that
control the low/medium fan speeds.  Also, any other things to check
before running out and getting new relay(s) (e.g. can one bypass the
radiator temp sensor on this to check the relay/circuit?).

TIA