Unexplaned voltage drop on the 12V wire from head unit ACC to reverse camera

[Charlie Whiskey]

Some electrical gremlin must be having fun with the new head unit I'm trying to install 

The problem is my new reverse camera not powering up and I traced the problem to the 12V wire that is supposed to supply the power.

Both the camera and the RCA signal cable are fine - I know because I tested them with a separate power adaptor (i.e. from the wall socket) and the head unit displays the image from the camera just fine.

I tested the 12V power cable however and it was only giving me 9 to 10 volts and strangely fluctuates a fair bit.

That 12V power cable is connected to the head unit's ACC cable with a T-tap connector. I had another equally long cable T-tapped to the same ACC wire and that is giving me a steady 12V.

Any obvious ideas I should check for before I pull the head unit and all of the trim panels apart again? I'll probably break a few more pieces of plastic doing that... 

My chief suspect right now seems to be that T-tap perhaps not done right.

[IanB]

If you have two sides of a T-tap and one side is giving 12 V while the other side is not, then the signs would point to a fault inside the T-tap, or a fault in the wire leading from the T-tap. It is not likely the fault is upstream of the T-tap.

[Charlie Whiskey]

Found the culprit!

Turns out this connector wasn't quite done properly, and I know the wire was too thin for it. The insulation was holding it in place, but the conductor itself was basically floating in air.

A drop of molten solder solved it. Gremlin terminated. 

[CaptDon]

I have run into that scenario several times on a boat that I operate. The boat had a fire many years back and the company who was working on the boat and caused the fire agreed to fix the damage at their cost / insurance. Apparently one of their numb nuts electricians thought that those spade lug connectors were designed to bite through insulation like a T-tap. I have had an endless group of failures. No power to bilge pumps, announciator lights not coming on to warn of certain conditions, intermittent power to other ship systems. What a nightmare!!