Wiring, the good the bad and the UGLY

As most of you know I am a glutton for punishment when it comes to projects.

Been woring on a diesel Blazer (84) and just this weekend decided to swap out the body in favor of a nicer cleaner one I found.

OK
The issue right up front is that the project truck is a 6.2 diesel truck YEAAAAAAAAAAAAAAH :D and the truck that ahs the good body is a gasser. BOOOOOOOOOOOOOO :(

These facts dictate the real need to swap all the wiring harnesses from the 84 diesel's original body into the Donor body.

The engine wiring is fairly easy to get to but, on the other hand all the wiring under the dash is a real @#$%^& to get at.

Been carefully disecting the diesel rig over the last several days and discovered a lot of real issues with the wiring.

First off, the wiring on these older trucks is not all that complicated but its just packed in under the dash pretty well.

The dash has to come all the way apart to gain good access to this stuff too.

Once the cluster is out, then the pad comes off, the glove box comes out, dop the steering column down a little bit to gain more room.
All the HVAC ducting comes out and WOW you can actually see what your working on.

The issue that brought me to writing about this is simple. ELECTRICAL ISSUES.

Last eavening while slowly unhooking plugs and tracing out where stuff goes, I decided to remove the ground BUSS BAR over by the drivers side AC duct. WHHHHHOOOAA once the sheet metal screw was out it was real easy to see a real pile of corrosion under the Buss bar where it contacts the sheetmetal body.

Looking at the area one would never see this issue.
Also to get to this stuff is really tough too unless you are getting serious about removing half the truck.

Further investigations revealed that many of the connectors had corrosion in them.

Most all can be cleaned with contact cleaner and dialectric grease applied to restore them to full function.

With many of our trucks reaching back 20+ years or more, the issues with wiring are becoming almost epidemic.

For the folks that live in the salt belt, the issue is even worse.

Here at TDP we are always telling folks to check Grounds and other connections before spending $$$$$$$$$$$ on repair parts.

This little excercise last eavening really brought this stuff home.

The practice of using the sheet metal body as the ground has been a practice in the auto industry forever,sadly it has its downside.

Over time, the various joints all around the vehicle accumulate dirt, moisture and corrosion and this stuff all goes to work destroying what was once a nice system of grounds that kept all the onboard devices working.

So after 20+ years, things like the electric windows, heater blower and other goodies all start to suffer.

Now spring forward into the age of the computer, do we have any better grounding, nope not all all. The computer controls hate poor voltage supply and bad groun ds can drive this stuff nuts.

The +++ wiring usually has weatherpack connectors with the cool little bellows to seal them. What about the grounds???? Just a sheet metal screw with a star washer in many cases, buttoned up to the good old sheetmetal body.

We speak of checking all the grounds when looking for electrical issues.

OMG there are grounds in these things that have not and will not see the light of day since the truck was assembled at the factory many long years ago. :eek:

To totally disect a rig to check the wiring is not something that most folks are willing to do or even think about. :(

The only real way to even know where most of this stuff is, requires the factory wiring diagram book and even that does not always tell you exactly where the stuff is.

Its amazing at how nasty so many of the connections were that I pulled apart.

No wonder the tailgate power window had failed several years ago.

Keep in mind, that when connections get corroded, the voltage available drops, and as that happens, the amperage draw goes up. With this comes heat and ultimately component failure.

The once gentle whirrrrrrr and very quick action of the power windows become a noisy growl with the window requiring a helping hand to get it down and then a little prayer that it will come back up again. :eek:

I will also add that the designers of these things had not planned on someone taking them totally apart.

These vehicles go together in LAYERS with the stuff you will need to service being burried under a pile of stuff you will never need to touch. :confused:

OMG what a task to strip out everything in the way of wiring, inspect it and reinstall it.


Hope this gives some others a little insight into what happens behind the scenes as your rigs sits out in the rain year after year.

Dialectric grease is good stuff.

A great plan and one I intend to employ during the reassembly of my Little truck is to add a ground wire to the ground Buss bar that runs to the NEG battery terminal.

This should go a long way to making things work far better.

Sadly the Buss Bar ground fastens to the inner cowl, then this is ground by metal contact to the fenders and if they are still there, ground straps that connect tha body, fenders, frame and engine all together.

So many times during repairs these ground straps are either removed to gain access or damaged or just tossed off into the corner.

Any ground strap needs to be there for a specific purpose and was installed at the factory for that specific reason.

The factory does not spend $$$$ on anything that does not serve a real purpose.


Best to all


Missy

Electrical diagnosis is my specialty. Although a bit novice to "older" diesels like the 6.2L, I am an ASE Master Automobile Technician and ASE Master Truck Technician, with L1 and L2 Advanced Level certifications,as I teach High school Auto Tech now (3 years). Grounds grounds grounds grounds grounds GROUNDS!!! Most of the drivability issues, and electrical/electronic issues I see and fix are grounds! The plus side of that is that grounds are east to fix, even if you don't have a factory manual. If you have a digital volt meter, an easy way to check for poor ground performance is simple. Hook the positive lead of the meter to the negative of the component (for example, lets say it is a blower fan we are checking). To do this, use a paperclip to backprobe the electrical connector (the component needs to remain electrically connected). Clip your positive meter lead to this backprobe, and then clip your meter's negative lead to a known good ground. Now operate the component. If the meter reads more than about 0.5V when operating the device, the ground is bad. Also, if it is a sensor or sending unit, that number is even lower, as many engineers want the voltage drop on a sensor circuit ground at less than 0.1V, and some even specify 0.05V. How to fix that? You could dismantle half of the truck, or, you can just splice into the ground wire and run a new ground. Don't skimp on the wire gauge, make it nice and thick.

:D:D:D

Yeah buddy Grouuuuuuuuuuuuuuuuuuuuuuunds as in - - - - - - MINUS side.

My Western Star class 8 Rig has an individual ground wire for every component that runs all the way back to a common heavy buss bar.

None of this grounding stuff to the sheet metal.

I have seen more troubles with trailer lights even on big rigs, due to GROUUUUUUUUUUUNDS..

The farther we have come into the use of the computer on the rigs, the more troubles we see with electrical issues due to Bad Connections and usually grounds.

I would rather eat my way through 5 nasty miles of busted crank shafts rather than chase an electrical issue thats burried under the dash where you cant even get to it. :eek:

What makes it worse is when some idiot owner adds a bunch of aftermarket goodies, and wires stuff in with a bunch of hashed up crimp over splices that maybe cut the insulation and maybe they dont. :(

Oh yeah seen it all in my 40 some odd years of wrenching. (Been wrenching on cars since I was 16 and have done it for a living off an on)


Missy

Unlike many motorhomes, my Barth was top-of-the-line when built. There are NO sheetmetal grounds; all grounds go to a bus, which is connected itself to a chassis ground. Cleaning grounds is simplified because they can be traced.

But Barth must've gotten a deal on bus bars, because there are seven...

Quote:

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Originally Posted by Robyn

:D:D:D


Oh yeah seen it all in my 40 some odd years of wrenching. (Been wrenching on cars since I was 16 and have done it for a living off an on)


Missy

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Gotta love a girl who can say that. In fact, if you were closer I'd ask you to come in to talk to some of my female students, to show them how much opportunity there is in this field no matter your sex. Allot of the girls in my neck of the woods are somewhat of the opinion that this is "man's work" and some girls who like auto tech and try to pick it for their shop are denied by their parents for the same reason. The worst part about that flawed logic is that many of my successful students have been women.

I took auto shop in High school (late 60's) instead of HOME EC (YUK)
Went to college and majored in auto tech.
I was the top student of a 2 classes totalling 300 people. (Ages 19-35) This was a community college and had quite a cross section of age groups.

Went on to go through GM training center.
After all the schooling I went to work for a manufacturing company and served a 4 year apprenticeship.

I already knew how to weld but went on to certify in a few special areas.

Got my journeymans ticket in Spring of 1977.

Cross trained in the machine shop and subsequently got my Journeymans ticket as a machinist too.

(Now this was back in the days when the CNC was just coming into being.

We had the old school Bridgeports, Lathes, large verticle and horizontal mills. and two huge planer mills with 40 foot beds on them.

Ahhhh yes, the good old days.

Women today need to look at the history books. During WWII most of the factories building everything from B 29 Bombers to Sherman tanks were staffed with women.

Today the stereotypical jobs are really a thing of the past.
Women drive heavy commercial trucks :D Fly Jet liners, pilot huge ships and on it goes.

I do believe that the Space Shuttle has had a female commander a time or two.

I see women running heavy Pit trucks in the quarries.

Any parent who does not want there "LITTLE GIRL" to work outside the so called womens work arena are just dooming that little missy to compete in a very narrow market.

My daughter is a stay at home mom, but has worked in various jobs. She chose to do retail and such but she could handle a big rig if she chose to do that.

Very little work these days requires BRUTE strength to do. Hell thats why that make pipe to go on the end of the wrench ya know :D

The old idea that girls make better students, because they will listen better and not have a Macho attitude ??????????//

I have met a lot of girls that dont listen worth crap, can't follow instructions and just plain screw up.

You have to want to do the job right, then the rest is easy.


Missy

Some of the best Naval Officers I had serve under me were female (and some of the best enlisted, too!) - and that includes US, British Commonwealth, and others.

Has this thread been hijacked, or what?

If all the girls had to pass home ec, maybe we'd have fewer obese kids?

(Slightly tongue-in-cheek...)

Seriously, there are too many families out there with no member who understands the meaning of a balanced meal.

Yup sure does look that way eh :D

Oh well, stay tuned and maybe it will find its way back on track.

Thats what happenes when ya have BAD GROUNDS dont ya know :rolleyes:


Missy :)

Quote:

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Originally Posted by Robyn

Thats what happenes when ya have BAD GROUNDS dont ya know :rolleyes:


Missy :)

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Had a customer with SAAB once. Ironically, it was while I worked at an Olds dealership. He liked my work so much he brought me his non-GM cars too. He had a peculiar problem, where if he turned on his fog lights, all his windows would roll down. Turned out that a faulty relay ground was back-feeding current from the fog light circuit through the body control module and activating the express down feature. This ground, by the way was way up under the dash and to get to it you practically had to tickle the back of the VIN plate from underneath. I snipped it, spliced it, and ran two heavy duty grounds... one for the BCM, and one separate one for the fog lights. Everything was back to normal. This was in the days before AllDATA, and GM didn't own SAAB yet. We didn't have any manuals for this car. But with some basic diagnostic work (voltage drop testing), I was able to effectively repair it without diagrams. Not that I'd recommend it, but the concepts work!

Quote:

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Originally Posted by Robyn

Ahhhh yes, the good old days.
I have met a lot of girls that dont listen worth crap, can't follow instructions and just plain screw up
Missy

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I can't believe you know my ex-wife missy,..she definitely wasn't well grounded either,.

Nick

Good Day!

As Missy knows, I posted this elsewhere, but what the heck - seemed like it fit here too..

Want a forever ground?

1. Sand the steel shiny.
2. Tin the steel w/ lots of flux.
3. Solder a brass washer to the steel.
4. Ground terminal screw goes through the hole in the brass washer. Drill & tap if thick steel, sheet metal screw if not.

I've used this to make the ground connection on a trailer harness, which is always exposed to weather. They go 5-10 years before giving trouble, at which point you just remove the screw, shine the brass, & go another decade. I would guess that inside a vehicle, they'd never go bad.

Blessings!

Great idea! I'll be sure to incorporate that one into my bag of tricks!