12V Wiring I

I spent some time this week designing and implementing the front 12V system. First, I drew out most of the engine compartment wiring (you can find a PDF here):


I then prepared the relay box. Here it is from the front. You can see the two main relays on the left and right. They are angled this way so the pins will be facing "down"-ish when the box is mounted - I don't trust this box to be 100% water-tight and this will prevent condensation from seeping into the relays. The relay on the left is a 240VAC DPDT relay to handle duties associated with detecting when the charger is plugged in (this is the lower relay in the circuit diagram). The relay on the right is a 12VDC DPDT relay to handle some keyswitch action (mostly: disable the DC-DC converter when the key is switched off):


Here is a view showing the top. There are two rows of 10-place terminal strips. The one in front is row "A" with terminal #1 on the right and #10 on the left. The one in back is row "B". These numbers correspond directly to A1, B2, etc. on the circuit diagram:


There are provisions for 6 keyswitch-controlled and fuse-protected circuits. I am currently using 4. There are also 4 glass fuses for the various signal wires that go out. My current philosophy: fuse early, fuse often. Much easier to replace a fuse than to put out an electrical fire.

Still to do: the charger interlock is drawn correctly on the diagram, but not implemented correctly (the DMOC wants the charger interlock to close a circuit when plugged in; my implementation currently sends a +12V signal, which is not the same thing). Also, this implementation currently disables the DC-DC converter when the Jeep is plugged in. It seems like a good idea to be able to optionally charge up the 12V aux battery when the key is turned on. Again, the wiring diagram above is correct, but the implementation is not quite right yet.

Next up: still have to remove the rest of the dash so I can get at that heater core... you might be able to tell that I am procrastinating on this less-than-fun chore.