The arrow indicates the pin is an output on the module. The ground symbol inside gives you a clue what to expect when active. These look like open collector outputs, meaning they supply a "ground" to the external solenoid or relay they are activating. In all these cases I would feel safe substituting a physical ground (jumper to ground) to create the same effect, or if you wanted to see if they were active, a test light referenced to battery + would be lighted when active.
Instead of jumping the relay 30 to 87, you would just supply the ground to the relay coil to have the same effect, which at the same time verifies the relay works.
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Art Benstein near Baltimore
"Shun those who say we have eyes in order to see, and instead say we see because we happen to have eyes."
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