Waning Wiper Wiring

["W.B. Peale" <peale@domain.elided>]

I've been attempting to diagnose a problem with the windshield wipers on my
69 GTV with no success.  I thought I'd throw it out to the AD.  First
relevant fact is that I am a complete electrical idiot.

The wipers worked intermittently for a while before dying completely just a
few days ago.  I tested the wiper motor with a hot lead from the battery,
and it seems to work just fine in both speeds.  I tested the leads coming
off the incoming wires, and while the switch seems to work properly, my
guess is that the amperage in the leads to the motor is low.  When I connect
them to an ice-pick-style circuit tester, the little diode in the handle
burns very faintly, as opposed to very brightly off a good hot lead.
Voltage seems OK at just under 13v.  Could something (old wiring) be causing
high resistance in these leads?  Any ideas?

Thanks,
W. B. Peale
69 GT Veloce who can no longer bat her seductive eyelashes

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