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I've been working on my 55 Chevy truck for over 3 years now. I have the cab back on the frame and a new 350 engine. I had bought a 58 panel for the 4x4 running gear that happen to have a new updated wiring harness in it. I am now about to install that harness in the 55. I am new to wiring and am feeling a little insecure. I keep pulling the harness out of the box, spreading it out, and then putting it back in the box. I just don't know where to start. I'm even confused how the negative side of the battery is grounded. The factory manual has it mounting to the cab behind the battery, but I've read forums saying it should be grounded to the frame. And then there is the engine, grounded to the cab or frame?

Any suggestions? Any stories? Any Tips?

Thanks
Michael

Sounds like you have a wiring kit ? It really isn't that difficult to do - just follow instructions / take your time. Most Kit suppliers have pretty good Tech. Help lines if you get stuck. It is very important to get good grounding - amazing how many problems that can cause. Battery can ground to frame, or engine block. Body OK as long as you have a good connection between frame and body parts. Some guys run ground straps between motor, body, and frame to be sure. Decide where you want to put your Fuse Box, then all runs from there. Solder any splices, make sure crimp-on connectors are firmly on, and use rubber grommets where wiring passes thru metal. When I did mine, it was first major wiring I'd ever attempted - took a while but all works OK now.

Ideally every thing should be grounded. I'd run the negative cable to a starter or bellhousing bolt. Then I'd add a strap from engine to frame, another from cab to frame and another from bed to frame.

As far as running the harness, take it a piece at a time. I used a Hot Rod Wires harness on my '56. I mounted the fuse box first then ran each system one at a time from there. I left the rest of the wires hanging out the door while I was working. I know it looks scary when you look at that big old bundle of wires, but as long as you take it a piece at a time it's manageable.

Good luck.

Michael,

Sometimes it's easier to do a task if you chop it into little pieces..it's much less daunting that way. I don't know how much alike your '58 panel harness is to your '55 pickup harness but they are probably close.

I think the best place to start would be in the middle, in the dashboard area. None of this stuff is negotiable, it's pretty well fixed. Get the middle piece situated and lock it down with a few zip ties. Now you should have a basic leg that runs forward and one that runs back toward the rear. Those are the little bits...the middle hunk, the front hunk and the back hunk.

You can make a list that shows all the items that need a wire run to them, things like the alternator, the coil, the temperature sender, the fuel sender, the brake lights. Look the rig over and think of every 'to' location. Now all you need to do is find a 'from' wire. It's a state of mind, you can do it. Your only obstacle might be the differences in the harnesses between those two years. Draw a bunch of pictures and study them, you will do fine.

Stuart

Thanks for all the responses. Sounds like I should ground everything to the frame for good measure? Why doesn't the factory manual ground the battery to the frame?
By the way, this 58 had a new universal wiring harness, probably from Painless or some other company (I couldn't find a logo on it). I don't have the manual but luckily the wiring still had the tags where the "groups" went i.e. rear tailight group, headlight group, radio group, etc. When removing I added my own labeling as well so that should help. I replaced the points distributor with an Accel breakerless one. It says to bypass the resister, is that correct? The altinator is a late model internal regulated, do I need to keep the voltage regulator?

This stuff is intimidating!

Michael,

You're about halfway there already, good job! You would have to consult the Accel literature about the ignition resistor, I think some aftermarket units use it and some don't.

Yes...you can dump the old regulator on the firewall. Put it in the 'For Sale' section.

Stuart

With my Painless kit, the wiring follows GM colour codes, as well as being labelled every foot or so.

Frome Atomarc; "Ideally every thing should be grounded. I'd run the negative cable to a starter or bellhousing bolt. Then I'd add a strap from engine to frame, another from cab to frame and another from bed to frame".
Why doesn't the factory manual show the battery or the engine grounding to the frame? I currently have a braided strap from the engine to the lower cab, and from the negative battery to the cab as per the manual. Should I run a long braided strap from the cab to the frame? Maybe the same place the negative bat. strap attaches to the cab? Shouldn't that "connect" the cab, engine & battery to frame?

I was the one who posted that statement.

To answer the last question, yes, you should run a strap from the cab to the frame. This is to assure you have ground for your tail lights. They ground to the bed which is attached to the frame. When everything is new this is sufficient. However, once the bed bolts start getting rusty it affects the grounding. That is why I also like to run a strap from frame to bed.

As to why the factory manual doesn't show a ground to frame I can't answer. Perhaps because when it is new there is an effective ground through the cab mount bolts. But, like I said about the bed mounts, that connection will deteriorate. I like to use redundant systems to assure good grounds. I don't like troubleshooting electrical systems.

jomichael,

* You're have received lots of input so far and probably more to come. some of us buy wiring harness and hope we end up w/ something that fits closely to our beloved trucks or vehicles.
* That being said you are in good hands by asking questions as clearly as possible. better stated querries result in better understood answers. NO queerie is stupid! . ask away. some basic questions you have asked were covered in high school autoshop 101. to help this lesson along about grounding, many bolters have simple problems because they think all is well in boltville. most of our bolts origionally came w/ two single ground straps, one from the engine to the frame, the other from the battery to the frame, (not to confuse you some were grounded on the positive side of the battery) but we're NOT doing that here! old vehicles were grounded together because everything was metal. those problems bolters have is becaues may times the lack of a GOOD ground causes them. so real headaches for many. a good ground means that the painted surface must be scraped away down to bare metal on the cab, bed, gas tank, main truck frame, radiator frame, engine and/or cab. however you wish to look at this. if you do a ground up restoration it's always nice to ground everything I've listed for electrical reasons cause everything has a fresh coat of paint on it.
* Blinkers, tail lights and headlights are dim or don't work because of poor grounds. SO if when putting your harness in pay attention to well groundede wires.
* some tricks can help, i like to use a serrarted lock washer against the body and the wire's solderless connection. i also like to coat each grounded wire because if you leave the bare metal surface along rust and/or corrosion can more easily start thus preventing a good ground. ask at any parts house for a battery paste or spray coating. If all grounds are correctly done and a particular item does not work you will have an easier issue to trouble shoot the pos 12V side. a cheap VOM and simple trouble test light http://images.google.com/imgres?imgurl=http://www.2carpros.com/dia/images/test_light.jpg&imgrefurl=http://www.2carpros.com/dia/test_light.htm&usg=__8Du796Ivz6TIUc5hh-rDlQ0io5I=&h=341&w=521&sz=22&hl=en&start=1&um=1&tbnid=WkN4gzfavZKpiM:&tbnh=86&tbnw=131&prev=/images%3Fq%3Dtest%2Blight%26um%3D1%26hl%3Den%26client%3Dsafari%26rls%3Den-us%26sa%3DN
are nice to have. the battery braided strap has to be as big as the battery positive wire. i use a 2.0 gauge wire and a double flat strap braided for the ground to frame (coated @ the frame).
* example of a good ground, photos are worth .....
http://s67.photobucket.com/albums/h298/1951otter/?action=view&current=2650080-R2-014-5A.jpg
http://s67.photobucket.com/albums/h298/1951otter/?action=view&current=2650080-R2-008-2A.jpg
http://s67.photobucket.com/albums/h298/1951otter/?action=view&current=0732700-R1-036-16A.jpg
as you remove the new/old harness take notes. if you can try and figure out what fuse powers what?? on your truck. the better the records you keep will make life so much easier to you in the future. i use an excel spread sheet to show what main fuse is linked to what minor fuse to a specific feature (radio, cigar lighter, heater, Ign, lights, or ??) I would run every ground to the main frame because the frame is everywhere. your head and tail lights, battery and cab all come close contact to the frame. your taillights are not close to the cab.
i run
battery to frame
cab to frame
inner fender to frame because i have all my relays mounted on my inner fender.
gas tank to frame.
bed to frame.
engine to frame.
most all of these ground wires are 8-10 gauge and because
i work telecommunication i have access to 'find' these. most are crimped and soldered and heat shrunk.
to help you to understand how some things are wired and some better ways of wiring are shown here...
http://www.madelectrical.com/electrical-tech.shtml

Cletis, sorry for not giving you the cred on that one! Thanks for answering my questions. Beware, there are many more to come!
Carolines truck, VERY HELPFUL STUFF! I will ground everything, and since this is a ground up resto, I'll make sure to remove the paint on these connections.

In reading the article about dim headlights and adding relays to solve the problem, it leads me to yet another question.

If I have a new modern wiring harness, is there a need for relays? Or junctions for that matter? I'm guessing not, but better not guess!

Thanks for all your help guys, this is giving me the confidence to move ahead.

Michael

There are many opinions on the need for relays. Mine is- with the proper size wires and good grounds, they aren't needed. The Hot Rod Wires harness I used in the '56 has 12 ga headlight wires. I'm running halogens. They are properly adjusted and light up the highway fine.

for various reasons i like relays regardless of an all new wiring harness and fuse panel.
read why in MAD Electric link above
relays run independent of fuse blocks because they work one system, need to be wired correctly as everything does. trouble shooting is easier to overcome, systems work better.