wiper mystery

[Wabbot@domain.elided]

I have an 86 Spider Graduate.  When attempting to operate the wipers in the 
intermittent mode the wipers will continue to run without stopping maybe 6 
out of 10 times.  The other times they will park.  Also when the wipers do 
park or when I shut them off from the continuous mode the brake light and the 
water temperature light in the instrument cluster will flash on and slowly 
dim to off within about a second or so.  When the wipers run in the 
intermittent mode and don't park there is a buzzing sound from the relay 
under the glove compartment.  With further investigation and opening the 
relay to watch it operate there was a green arc across the contacts.  I 
replaced the relay to only have the same problem.

Anybody got any clues or answers?

TIA,

Wayne Abbott
Durham, North Carolina
86 spider
76 alfetta GT

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