When I took off the dash panel under the steering column, I found this silvery "black box." What in the world is this? I thought this machine was old enough to be non-electronic!

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'75 John Deere 450C (times 2)
'83 240D plus parts car
'87 F350, 6.9L IDI
'89 F350 crewcab, 7.3L IDI
'89 F-Superduty, 7.3L IDI
'91 F-250, 7.3L IDI
'91 F-350, 7.3L IDI
'94 F-350 Crewcab, 7.3L IDI
'94 E-350 Ambulance, 7.3L IDI