I suppose I ought to know what this is, but I don’t (part circled). Doesn’t look like a voltage regulator because of removeable cover. Relay for something? This is the passenger-side firewall of ‘63 FJ40. I don’t have the part on my ‘63 FJ45 but I do have the factory weld nuts there so something must go there, and it has wires coming from it, hence the question . Thanks!