best place to steal switched power in rear of truck

grunge311 · 11-17-2005, 12:27 PM

I need to steal some switched power from something on the rear of the truck. I currently am stealing from the reverse lights for my reverse camera, but I would rather have it powered while driving so I need to steal a switched power source that I can wire it from. I have the big tow so I was thinking there but I don't know what wire, and I havent had the recall on the BCM thing yet so I don't know how smart it would be to steal power from there.

bestatchess · 11-17-2005, 12:56 PM

I would suggest probing the pins of the 7 pin trailer connector with a volt meter or test lamp to see if one of them goes to +12V with the ignition.

I don't think they would even notice if you spliced under the truck, back from the connector a little ways, and put everything in split loom and wrapped it with electrical tape. For their BCM/Harness recall, they test pins 2 & 5 (which should not be hot). I think the pin you want is a different pin that is supposed to be hot.

cttitan · 11-17-2005, 07:14 PM

Well according to the wiring diagrams in the service manual pin 5 should be hot in ON and START. See the attached word doc showing the service manual wiring schematic.

The BCM fix test has them testing for voltage on pin 2 or pin 5 and apparently it shouldn't be hot in the ON position??? I don't understand it. Pin 5 is your 12 volts to the trailer battery for charging it so it has to be hot in ON.

Does anybody know what the new harness really does? The line is fused at 30 amps so a short in the trailer should blow the fuse.

scr38 · 11-17-2005, 07:42 PM

The wiring in the Service Manual is incorrect. The diagram on the cover of the trailer socket is correct. Switched 12 volts is on pin 4. I would post the correct pinout, but for some reason I don't have the option for attachments. Has something changed here?
EDIT---------------------------------
I see the problem. While in Firefox (my usual browser) I don't have an option to make an attachment. I am in IE now and will attaach the corrected pinout for the plug.

bestatchess · 11-17-2005, 08:12 PM

So I think the answer to the original question of where to tap to power a backup camera at all times that the ignition is ON would be on the wire connected to pin 4 in scr38's corrected diagram, and which is marked with a + on the hinged cover of the Big Tow wire connector, correct?

scr38 · 11-17-2005, 10:14 PM

Quote:

Originally Posted by bestatchess

So I think the answer to the original question of where to tap to power a backup camera at all times that the ignition is ON would be on the wire connected to pin 4 in scr38's corrected diagram, and which is marked with a + on the hinged cover of the Big Tow wire connector, correct?

That is correct!

cttitan · 11-18-2005, 04:17 AM

Quote:

Originally Posted by scr38

The wiring in the Service Manual is incorrect. The diagram on the cover of the trailer socket is correct. Switched 12 volts is on pin 4.

Thanks SCR38, you always come through. I didn't want to go out in the dark freezing cold to crawl under the truck and see what was up! I'll have to update my info.