Solved False reading of 30 volts DC at front and rear 12V power points!

[lcrum1]

1. Hi all - new member, first post. I just bought a used 2007 Explorer EB V8. Going through it finding all the little things wrong I need to fix. (crappy lighted visor covers broke, etc) Discovered that both the front and rear power points are not working. Checked the fuses (21 and 25) in the Power Distribution Box - both good. Grabbed my multimeter and was surprised that I was showing around 28-30 VDC at both sockets. Started taking things apart a bit to see if maybe I had a ground problem or an obvious wiring issue but I couldn't find anything. Wanted to throw this out there before I get too far into this. Has anybody seen this? Every thread I've found is usually one or the other power point dead and most times the fix is a fuse or new socket. Might need a wiring diagram? Any input would be appreciated!! I'd rather not re-route a 12 volt straight source off the battery as a fix unless I have to. Thanks in advance!!

 

[07EddyB]

Check your meter directly on the battery.
You have a 12 volt electrical system. Unless someone added another battery in series you cannot magically have that much voltage.

 

[Josh P]

28VDC or 2.8VDC? Corrosion in the socket or connector on the back side of the socket would be my guess if you are getting a reading on your volt meter above 0.

 

[lcrum1]

Solved - my Fluke 16 Multi-Meter had a weak battery. Changed the meter battery - got 12 VDC, cleaned up the front receptacle corrosion (I think those always seem to get something spilled in them). Both working fine now. Thanks for the replies. Great forum!

 

[BrooklynBay]

Welcome to this forum! My first thought that it was an alternator/regulator issue, but even then you won't get that much voltage. I'm going to mark this thread solved.

 

[08EddieCA]

07Eddy and BrooklynBay,

Sorry for the CPR of this thread - I'm diagnosing a similar problem.

I have two of the three power plugs not functioning. The only one that works is located within the armrest. I replaced the battery (AAA came over and installed the battery) and the alternator.
In the morning I'll check the fuses, ground, and check for corrosion.

These two power plugs stopped working after my transmission was rebuilt a month or two ago. I asked the tranny shop if they removed the armrest however their response was less than helpful...
FordParts.com might have a wiring diagram, I'll reference the diagram too.

Thank you!

((2008 Eddie Bauer A4X4. 4.0L V6 - recent trans rebuild, new battery, and alternator - ~130K on the odo.))

 

[tripplec]

I can surmise there is an independent ground for them that is left disconnected underneath then. East confirm, find another ground up front somewhere and check against the positive tip in the socket. If its 12V then you know for sure and it like dead to the meter if you return the ground lead to the socket collar.

 

[koda2000]

I'm not surprised the problem was with your multi-meter. Pretty hard to get 28-30 volts out of a 12V system, whose max voltage should be around 14 volts with the engine running. If your alternator was putting out 30 volts you'd have fried everything on the truck and be smelling rotten eggs from a cooked battery.

 

[tripplec]

1. I have use meters as long as I can remember. Personally still like a good analogue meter which I have as well as 4 or so digital ones. Analogue meters are much better to see real variation, and properly. While most digitals will jump around and you don't really know if its the connection or leads. I never see a digital meter read anything like that with a weak batter. They usually show low batt symbol and/or dim and go blank in time. I think that's something Fluke should address for what people pay for them.
2. Yes Koda2000 is right (don't know why I am getting this numbering going on now)

 

[08EddieCA]

I confirmed with my voltmeter the plugs are dead, except for the one within the armrest - 12.22 V.
I'm going to remove the armrest and see what I can find.

 

[tripplec]

Well I presume you verified the fuses are all good with the meter and there is 12V at bot fuse tabs.

 

[08EddieCA]

Well I presume you verified the fuses are all good with the meter.

Correction: Fuse was blown. Presumed solved. I will replace fuse and inspect operation of the plug. Thank you.