Cig Lighter problem

[Moparinho]

thanks engineers for you nice picture.  I appreciate it.   Belove there's my actual situation.

I have to add that I have 12VDC only between the lighter power feed and the instruments panel  (with lights on).

No tension between power feed and lighter frame.  How the grounding should be brought to the lighter frame ?

[the_engineers]

Check your fuse.

[Moparal]

Here's plain English.  The red wire that hooks to the stud on the back of the lighter should be hot all the time. Plain and simple. If not, you have the wrong wire hooked up or a bad harness.

The whole dash is grounded as it is. If the battery ground is hooked to the engine and the body ground point, the whole car is grounded.  The ash tray housing is bolted in with 3 screws to the dash frame. So now it's grounded. The 2 piece lighter receptical screws into the ash tray housing. So now its grounded. The lighter itself has the coil in it. It directly feeds into the red wire plug and the side of the lighter itself gets the ground from the side of the tray housing. This is a very simple thing here.

You can take the whole thing out and bench it at the battery to make sure it all functions right first.  It's only a 1 wire hook up and the ground.  So if you dont have a body ground or a live hot wire, it isnt going to work right. Plus the instrument lights runs on a lighter gauge fuse. It cant carry the amp load for the lighter.

[Moparinho]

did you ever find lack of grounding on the dash frame due to the paint coat on it ?

[the_engineers]

For the entire dash...no.  Easy enough to check, though.  Hook up a wire from the ground post on your battery to one side of your multimeter.  Hook the other side to the dash frame.  Should be VERY little resistance, if any.

...however, if that were the case, none of the electrical devices in your dash would work...

For individual connections, just sand a little of the paint away or use star washers that "dig" into the dash a little.

[Moparinho]

I gonna make some more try and I will let you know news if any.

Anyway, thanks everyone for the help provided so far.

[Moparinho]

I don't’ want to bore you guys, but I really would like to improve my electrical knowledge.  So, I ask your help again.

Just a quick recap:

-   The negative pole of  the battery is grounded on the car chassis and engine.
-   All wiring under the dash is based on the assumption that the dash frame provides the negative grounding to all electrical services.
-   In order to have a 12VDC each service has to be connected to both the dash frame and a positive pole as well

Now, I have connected one terminal of my tester to  the positive pole and the other to different points of my dash frame.  I always got 12VDC.

But, I get 12VDC  also if I connect my tester to the positive pole and to the lighter power feed plug !?!

My conclusion is:  the lighter feed plug provides negative grounding.  And now I’m gonna be very confused ! 

Can you please give me your feedback to understand if there is something wrong in my assumptions or in my conclusion ?

Many thanks. 

[the_engineers]

Now, I have connected one terminal of my tester to  the positive pole and the other to different points of my dash frame.  I always got 12VDC.

Where are you sourcing your 12V from..at the battery, or at the fuse panel?  If you're at the fuse panel, make sure you're testing using the BATT terminal, not the ACC one.  That way, you know you have 12V all the time.

[Moparinho]

I'm sourcing directly from the battery with a long tester cable.  What is the difference between BATT and ACC ?

[the_engineers]

BATT is the straight feed from the Battery - 12 VDC all the time.

ACC is the switched feed through the ignition system - 12 VDC when the key is in the "on" position.

[the_engineers]

How many Ohms from the Red lighter power wire to the dash frame?  This should be infinite or the opposite of 0, depending on how your meter reads.

If you have continuity (0 Ohms), you have a short.  Should find a blown fuse as well...

[Moparinho]

I found the problem.  The taillight fuse was blown and the paint on the lighter frame avoided it to be correctly grounded.   

I replaced the fuse and did a wire bridge to bring the ground to the lighter socket.   Now it works fine.

thanks to everybody.

[the_engineers]