[AT] Grounding, the final chapter

[Joe Hazewinkel]

OK, problem solved.  Sometimes the fixes are easier than you think.  First of all thank you all for your help, the discussions really got me thinking.

The story starts here, about two years ago I had a really nice custom bed made for my truck.  They wired everything for me during the install.  I haven't towed my big trailer since then because my tractor buying has slowed to a crawl, and my time is limited.  Anyway, I have been assuming that they put everything together right.  That was my first mistake.

When I mentioned that I have power to the brake prong, I was only getting 2-3 volts, I assumed this was due to the grounding issue.  After reading some of the e-mails today, I realized I needed to look at a copy of the wiring diagram for my truck to find the ground attachment point.  After looking at several different diagrams, one thing struck me as odd, they all seemed to indicate that the blue wire on the truck was for the brakes, mine was using the black wire.  A little lightbulb went on I my head.

Turns out the wiring diagrams were right!  The truck side of my plug was wired with the blue wire to the auxiliary prong, and black to the brakes.  I flipped them around on the plug, and guess what, now everything works!  I have a battery on the trailer that must have gotten a good charge the past few days.

Here's the only damage 1) My pride 2) new plug, $14.00 3) new brake controller, $140.00 4) about eight hours of my time!

As they say, now I know.

Enjoy, Joe

Sent via mobile device

On Oct 23, 2014, at 12:28 PM, Alan Nadeau <ajnadeau1 at myfairpoint.net> wrote:

When I was running a four truck fleet of pickups on a snowplowing route I 
adopted what had gradually evolved into a virtually trouble free wiring 
system.  The ground side was ground bus and everything went through that. 
Heavy cable from the battery to the bus and every electrical add-on was 
connected there as well.  For the brakes the ground wire ran from the buss 
to the trailer connector.  Every wire in the connector then ran to a 
weathertight junction box under the trailer and from there to the load 
points.  Light wiring was in conduit and a two conductor wire went to each 
light, they were all rubber grometted lights.  Brakes got grounded back to 
the junction box and the ground connection there went to the trailer frame 
as well.

I had zero problems with grounds after doing that which made it well worth 
the time it took to wire everything.

Something to keep in mind if you live, or tow in, the rust belt is that the 
normal wiring setup has the brake controller being HOT all the time.  New 
controllers feed a tiny voltage to the brake lead all the time to detect 
when a trailer is connected.  The ground and the trailer brake feed are next 
to each other at the bottom of the plug.  Get a little salt 
water(electrolyte) in there when the roads are slush covered and the 
controller will show something is hooked up when no trailer is there.  In 
extreme cases that little bit of current combined with the salt water will 
rot the contacts completely away.

My cure for that was two pronged, first step was to wire a 12V relay into 
the power lead to the controller, triggering it off an ignition hot circuit. 
Second step was to put a manual switch in that same power lead so the 
trailer brakes could be shut off when there was no trailer involved.  That 
manual switch was also very nice if I got caught on bad roads with an empty 
trailer as I could shut the brakes off at will.  Sometimes it was safer to 
run without brakes than to chance having the trailer turn into a sled.
----- Original Message ----- 
From: "Doug Tallman" <dtallman at accnorwalk.com>
To: "Antique tractor email discussion group" <at at lists.antique-tractor.com>
Sent: Thursday, October 23, 2014 11:28 AM
Subject: Re: [AT] Grounding


> Seems like Ford has some strange grounding issues. I've seen strange
> performance issues such as hiccups, surges and erratic shifts cured by
> adding ground straps. If you ground to the frame, make sure you clean
> all the other grounds and I'd probably add a ground from the battery
> ground wire at the block to the frame also. Doug T
> 
> 
> 
> 
> Joe Hazewinkel wrote:
>> Greg, mine does have the seven pin connector.  My truck is a diesel with 
>> two batteries, do you think it matters which battery I hook the ground 
>> to?
>> 
>> I figured Ford would ground to the battery, but no such luck. I'm going 
>> to have to look up a wiring diagram on-line and see if I can find 
>> anything.
>> 
>> Enjoy, Joe
>> 
>> Sent via mobile device
>> 
>> On Oct 23, 2014, at 9:54 AM, Easley, Greg <EasleyG at health.missouri.edu> 
>> wrote:
>> 
>> #10 stranded copper wire all the way back to the truck battery is a good 
>> solution.
>> Replacing the 6-pin round connectors with the 7-pin RV type helps too.
>> 
>> 
>> -----Original Message-----
>> From: at-bounces at lists.antique-tractor.com 
>> [mailto:at-bounces at lists.antique-tractor.com] On Behalf Of Henry Miller
>> Sent: Wednesday, October 22, 2014 9:46 PM
>> To: Antique tractor email discussion group; jahaze at aol.com
>> Subject: Re: [AT] Grounding
>> 
>> It shouldn't harm anything, and might fix some other unexplained problem 
>> as well.
>> 
>> Trailers brakes take a lot of power, if you tested with just a voltmeter, 
>> then I'd worry that the power line might not be able to supply full 
>> voltage under load.
>> 
>> 
>>> On October 22, 2014 7:57:37 PM CDT, jahaze at aol.com wrote:
>>> To follow up on my trailer brake problem, I have been able to determine
>>> that I have plenty of voltage to the brake prong on the plug when I
>>> ground it to the truck, and a drop in voltage when I ground it to the
>>> ground prong.  My guess is that I have a weak ground connection on the
>>> truck.
>>> 
>>> I tried to chase the ground wire through the truck wiring harness, but
>>> never did figure out where it was connected. What I'm thinking about
>>> doing is putting a jumper from the plug ground wire to the frame in the
>>> back of the truck to make a better connection.
>>> 
>>> Is there any reason this won't work? Or does the ground wire have to be
>>> connected to another part of the truck?
>>> 
>>> Enjoy, Joe
>>> 
>>> Sent from my iPad
> 
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