What is this part?

[BelgianHJ60]

What is this part? What can I replace it with? No part number legible.
It's mounted on my left fender, closer to the firewall than the voltage regulator. 1984 LHD HJ60.

Additionally, the voltage regulator is mounted close, but attached to the same mounting point is a small electrical thingy.
Anyone know what that is for? Size of a sugar cube, black.

Also taking suggestions on how to properly clean these old corroded terminals.
I cannot find any good replacement kits.

 

[1911]

Looks like a ballast resistor.

 

[sved]

I would say this is a resistor for your cigarette lighter.
85540-60010

 

[BelgianHJ60]

I think it might be 85550-90A00, resistor assy, pilot lamp. No idea what it does.

 

[sved]

That one is the resistor for the light bulb hidden behind the vent /heat switches.

12V bulb in a 24V Truck .