Battery Monitor through OBDII
I want to monitor my battery and alternator voltage readings for a short period of time. The OBDII connector, Pin 16, is a 12-volt, always-on, pin that is fused through Fuse 14 under the hood. And the OBDII connector has a chassis ground on Pin 4.
Would it be OK to plug-in a male OBDII plug that has wire pigtails and monitor pin 16 (12 volts always-on) against the chassis ground on pin 4 with a voltmeter? I would be careful to seal off all of the other pigtail wires. And I would be careful to ensure that I got the correct wires for pin 16 and pin 4. I wouldn't be using the OBDII connection for an accessory. It would just be a voltmeter.
I don’t have a cigarette lighter socket to plug a voltmeter into (and I haven’t done Pizzaguy’s ingenious “Always-On Mod for the glove box light”). Before I got the car, a mod was made to put a double DIN system in and so the cigarette lighter socket was eliminated. And I don’t want to do a fuse tap with the illumination fuses. And I really don’t want to bother running a temporary wire through the firewall to fuse tap into the under hood fuse box. And I don’t want to pull the Kenwood Radio out just to tap into the always-on wire that should be back there.
I’m sure there’s some voltage drop in the wiring going to the OBDII. But that might be useful to know, too. Since battery voltage is so critical for the Crossfire, I’d like to watch it more closely.