True Confessions

A little confession is good for the soul they tell me.
So here’s mine. Sort of along the lines of Stupid is as Stupid does, but, like many other things part of the learning process. And I was only partially at fault ... honest....

I have a bit of an electrical background and I’ve always been comfortable with wiring my own cars from scratch as well as chasing electrical problems in them.
Said cars being the simple hot rods we build and drive.
Today’s computer cars, another story and enough said there.

Most of you know I bought an enclosed box car trailer for an out of state move.
Couple of cars and a shop means you gotta do something.

The problem, not too big, but it did waste a lotta time.

I bought a USA manufactured 12V DC fluorescent trailer light for the potty room I built into one corner of the trailer.
The potty room, a decidedly good idea for the girls in the family ... at least in their opinion cuz some race track facilities aren’t as user friendly as they oughta be.

The light did not come with instructions.

Installed the light, noticed it had a black wire and a white wire.
Kinda interesting thinks I.
The usual color for DC wiring is red and black.
Figuring black is ground or negative I wired it accordingly.
The light didn’t work.
Went out and bought a new fluorescent tube.
That didn’t work either.

So in the middle of this little light extravaganza, I loaded up the 31 and took it to the Southland to my friends house for storage until the house/shop move was complete.

Now my friend is a retired phone company wireman and real sharp on wiring.
Specially so on DC.
We talked about it and decided black was negative and white was positive.
Taking our clues from the 12V DC standard of red = positive and black = negative.
Pretty much what I figured out before, but it was nice to have a well experienced guy agree with me.

We were kinda busy over the weekend and the trailer battery was sitting in the shop so things stayed as they were until I got home.

Once there, and figuring the battery voltage may have been too low to fire the fluorescent, I checked the battery voltage.
Said battery being a four year old Optima that had been sitting on a rubber mat since last summer.
12.2 volts. I’d heard the Optima’s hold a charge for an extended period of time and it seems to be true.
Figuring the long 14 gage jumper leads could have cut the voltage down as well, I charged the battery.
The light still didn’t work.

I gave up and took the light back to the trailer/RV supply house where I bought it.
Figuring I’d swap it for a good one.
The gal at the supply house, friendly and smart, runs the parts counter and cash register.
She pulled the light out of the box, walked over to a battery, touched the light terminals to the battery, flipped the switch and the light worked.
(*& $* (^ %& %^....
A little embarrassing to say the least.
Not cuz a gal was able to get it to light, but that I’d been so dumb.
Only thing I could figure was, maybe the tube was loose in the terminals when I tried it.

Got home, repeated the same test the gal did with my battery and the darned light lit just fine.
Hot damn, now we’re cooking.

Reinstalled the light, connected the jumpers, it didn’t work.
Double checked the voltage at the end of the jumpers, 12.3 volts.
More ^% ^%#$ _^$#....

Pulled the light again.
It was then that I noticed a small stick on label.
I’d seen it before, but didn’t look close.
The fine print says: black = positive, white = negative.

Reversed the wiring, the light worked fine.
Reinstalled the light, it worked fine and still does.
Pretty obvious that I’d reversed the polarity on the bench although I thought I was being careful.

Now some of you may be wondering why I didn’t simply reverse the wiring to start with.
Usually an ok idea, but some DC circuitry can be damaged by reverse polarity and even though I didn’t think it would be damaged, I wasn’t sure and decided to err on the side of caution.

So aside from thinking that the DC fluor light engineers were idiots and figuring I was right in there with them as far as the idiot stuff goes, it looks to me like the color code for a trailer light was done so it would match up with the typical AC wiring color code.
That being, black is hot and white is neutral.
Probably makes it easy for inexperienced people to run what could be some complex circuitry in the trailer.
Anytime you mix AC and DC, life can get interesting.

It sure got interesting for me.

Sometimes, when I wanna see the dumbest guy in the world all I gotta do is look in the mirror.
He is the source of most of my problems....

 

It's always the basic stuff. The more we learn the more we try to complicate the situation. Thanks for the confession. It's nice to know some of the smartest still get caught in the trap. I make too many mistakes to ever confess to any!

 

Sounds like a case of being too smart for your own good Thinking too much will always get ya!

 

My wife usually chimes in with these gems when I do something stupid(which is more often than I will EVER admit to)"Aha! The old case of not being able to see the forest 'cause there's too many trees in the way" or when I start out saying,"You know hon I was just thinking..." and she'll reply,"Oh? Trying to work without equipment again?"

 

You've discovered the difference between Electronics techs and electricians. I spent years working on 3-dimentional air search radars that could pick up & track a 1 foot square tinfoil box thrown out of a plane at over 200 miles away and I could microwave cook a seagull flying thru the beam full speed at 200 yards, but I get screwed up trying to replace a damned light switch in the house! Damned electricians think black is the HOT wire.

 

Yesterday I received the turn-signal swtitch you sent -- thanks much, pal -- and after reading the clear wiring diagram I know I'm in big trouble! The switch has seven -- count 'em seven -- wires which is two more than the main harness for the entire truck!

I'll do the 12-volt conversion before I install the turn signal switch because I have to add a two-light harness in the rear, plus there are some glitches in some of the old 6-volt circuits.

I just want to be very careful and not let any of the smoke escape from the wires.

 

I think we all been there, and as far as know that door will open for the rest of this life...fatchuk