Ayuh.
The ones with the yellow caps are the D1 and D2 connectors for connecting a diagnostic reader. Since RENIX does not store DTCs, and is "pre-OBD," you are limited in your use of scan tools. The only ones I can think of are the MT2500 (Snap-On,) and the DRB-II and MS1700 (ChryCo and AMC, I think.)
The blue "connector" isn't - it's a relay. I don't have one right there on any of my rigs, but I don't have OEM fog/driving lamps, so that guess is probably correct. (No, I can't read the moulding in the pic. I do, however, recognise the pattern - which is all that's really needed anyhow...) The aux fan relay is usually on the fenderwell, back between the ballast resistor (tan thing) and the EGR solenoid (black thing with vacuum lines on it.) It's also a DIN relay anyhow - I think all of the relays on the RENIX (and probably later) are standard DIN relays, which makes logistics a bit easier. I also use DIN relays for electrical mods, to keep the supply chain simple. (Same reason I use ATC fuses for light electrical protection, and I pick a light bulb I already keep in the spares bin anyhow - usually #194.)
How do I know it's a relay? Look at the top of the thing - that's the internal schematic moulded into it (should look the same as the blue box in the closeup of D1 & D2.) That's a Bosch DIN relay, avaialable pretty much anywhere for somewhere around ten bucks. You use them all over the place - so you may as well keep a couple of spares of the relays in your spare fuses and light bulbs box.
There is some diagnostic access through D1 and D2 for a multimeter, perhaps I'll scan a pinout and put up some tests on WiP one of these days. Just haven't gotten around to that yet...
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