I've been running my headlight relay to replace the OEM AUX relays in the D. Those have been working fine but I had just glued the relay onto an aluminum angle to mount them and installed a standard relay socket to mate to them.
Well that glue gave way so the relay has been laying in my relay compartment. So being very bored building products I decided to create the AUX relay. Not that the AUX relays need very high currents but the pins on the standard relay are really only manufacture rated to 25 amps. These "pins" are manufacture rated to 85 amps and I like the idea of using ring terminals.
The nice thing with the AUX relays is I can make them larger than the standard 1.1 inch square size of the standard relays. I then 3D print a box to mount it. I use MOSFETs that have a typical 0.001 ohm on resistance. My Fan Relays (and headlight and blower) use two of those MOSFETs. I'm using 4 of those MOSFETs so that resistance should be 0.00025 ohms but I measured it with 5 amps (my 60 amp supply blew out) and got 0.00054 ohms.
Again I'm not selling these yet because I can't keep up with orders on my old products. Building parts to sell just takes to much time and I'm running into parts shortages on some parts.