1988 3300 Open - Voltage drop when lowering engine hatch or honking horn

[Pluto]

Hatch opens right up, but trips if I lower it for more that about 2 seconds at a time. I can see voltage drop down to like 4-6 volts when I try to lower it. The horn is the next switch over, voltage will drop to 4-6 volts if I honk it. Is there a common ground for the row of switches? Would it just be corrosion on a grownd connection? Why does the hatch not drop voltage when raised, but does when going down? I tried swapping the switch, that didn't change anything. Replaced the hatch motor as well, that didn't change anything.