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      09-19-2011, 04:29 PM   #75
Lotus7
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Quote:
Originally Posted by Bill S View Post
Thanks L7, that would be useful to know.
I have ordered one up (£39.99 from amazon.co.uk but don't seem available on amazon.com). Unfortunately it does not have any indication when/whether it's working. I've also ordered a OBD breakout box so when that eventually arrives from China I should be able to connect a meter.
Today, I was able to check for power on the OBD - II port.

The good news is that the power pin on the OBD-II connector is always "hot", so can be used as access to the battery for "light load" accessories or as a way to connect a low current "battery maintainer" type charger or a solar panel charger.

However, one caution that should be observed is that this connector pin is fused at only 5 Amperes. That means that it's probably safe to connect a small charger like the CTEK 3300 (3.3 Amps.) or a 45 Watt solar panel, but nothing using or providing any more power.

To test the connector power supply I attached a digital voltmeter to the appropriate connector pins and monitored the voltage from the point the car was locked using the key remote.

Door open, car unlocked, "lighter accessory outlets": ON, Interior lights: ON: 12.40 V. @ OBD-II connector

Time: "zero" car locked, "lighter accessory outlets": ON, Interior Lights: ON: 12.40 V.

Time: 0:00:30 car locked, "lighter accessory outlets": ON, Interior Lights: OFF: 12.53 V. (Voltage increased because of Interior light "time out".)

Time: 0:02:30 car locked, "lighter accessory outlets": ON, Interior Lights: OFF: 12.53 V.

Time: 0:05:00 car locked, "lighter accessory outlets": OFF, Interior Lights: OFF: 12.62 V. (The accessory outlet timer shut off the outlets and other acc. circuits.)

Time: 0:10:00 car locked, "lighter accessory outlets": OFF, Interior Lights: OFF: 12.62 V.

Time: 0:30:00 car locked, "lighter accessory outlets": OFF, Interior Lights: OFF: 12.62 V.

Time: 1:00:00 car locked, "lighter accessory outlets": OFF, Interior Lights: OFF: 12.62 V.

Time: 1:01:00 car unlocked, "lighter accessory outlets": ON, Interior Lights: ON: 12.30 V. (Key Remote "Unlock Button pressed - Lights and accessory outlets powered up: Voltage dropped due to load.)

The 12 V. "battery" pin on the OBD-II port is pin (16)
The power ground pin is pin (4)

The OBD-II port power is fused through Fuse No. 3 (5 Amperes)
That fuse is in the "front" fuse block (located behind the glove box), not the big one in the rear fender.

Hope this is of some use. Please keep in mind that this test was on a NA car. It's possible, but unlikely, that UK, Asian or continental vehicles are wired differently.

This photo shows the voltmeter connections to pins 4 and 16.:
Attached Images
 

Last edited by Lotus7; 09-19-2011 at 04:43 PM..
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