Grounding Not Included?

[Ewr101]

So I've just acquired a 72 2WD Blazer that's in really good condition. I don't have any MAJOR issues with it at all. I figured the first thing I want to redo is the 40+ year old wiring and fuse panel. I'm going to go with one of the more popular ones mentioned in this forum. My question is, after reading the instructions for a few of them they say that there are grounds that I'll need to install that are not provided with the harness. Can someone tell me how many there are, what they are, what gauge wire would be best to use? I'm just guessing but headlights and tail lights? I just want to know the full scope of work before I jump in with both feet. Thanks for your time.

[Bigdav160]

They are probably talking about the ground straps

There are probably 4 or 5 of them on a Blazer

[Ewr101]

I hope that's the case, I'd be pleasantly surprised, but I don't believe it is. This is from the manual for the Painless Harness: "Note: The Painless Wire Harness Kit includes no ground wire except the black wire from the dash and headlamp connectors. You must supply ground wire (14-16 gauge) for all circuits." That answered one of my questions but still leaves the other.... Will I need to run grounds for 28 circuits? Is this just the Painless harness or are all of them like this?

[franken]

That seems an odd thing to have in the instructions. Most everything grounds to the body and back to the battery via the engine ground. The starter needs the most current so the engine ground is top priority.
The big negative cable from the battery should be grounded to the engine.
Some of this may not be exactly how GM did it, but it should work. I wrote both sides, but that may be wrong after searching... The engine grounds to the cab by ground straps off the rear valve cover bolts, the frame grounded to the body with ground straps near the front cab supports, and the bed grounded to the frame at some point. There may have been a ground to the fender and/or core support by the battery, but the fenders and core support need grounds one way or another. http://67-72chevytrucks.com/vboard/s...d.php?t=422234

I've seen straps at the valve covers and from the cab supports to the frame, at least.
Google 67-72 chevy truck ground strap kit and you'll find them. http://www.brotherstrucks.com/prodin...number=GSK6772

[Ewr101]

My gauges don't seem to read correctly so I'll be adding ground straps where I need and probably a couple extras just to keep the electrical gremlins at bay. I just don't know about the circuit grounds. I'll let this posting marinate for a day or two and see if someone who has done a full rewire before answers. I appreciate y'all's input!

[Bigdav160]

I see what you're saying. You are not asking about an OE replacement harness but a universal type. Then yes, most likely, you just get a fuse box with the + wiring. No connectors so you'd reuse your old ones.

[BKSS67]

Why not make it easy on yourself and get an American Auto Wire factory fit kit that is plug and play?

No offense but the "Painless" kit is far from painless

[jaros44sr]

Originally Posted by BKSS67

Why not make it easy on yourself and get an American Auto Wire factory fit kit that is plug and play?

No offense but the "Painless" kit is far from painless

Gotta agree....went with M&H, darren is great tech support, answered all my stupid questions, rewired some of my circuits(headlights, alt. moved to passenger side, electric water pump) to name a few, truly plug and play

AAW is supposed to be the same, but don tno....

I believe the grounds they are talking about are the OEM locations, bought the straps off of our classified board

[Ewr101]

I'm afraid I didn't state my question correctly. The AAW is the harness I plan to use (I didn't want to name names earlier) as it seems to have a good number of its wires already terminated. I also plan on replacing the factory ground straps between the block, frame and body and add a couple more. What I'm questioning is, are there more AAW wiring harness grounds that I'll need to buy 14-16awg wire for to run and terminate and if so, does anyone know how many more and what they are?

[franken]

As mentioned, most everything only has + wiring and grounds go through the body.
Think about the headlights (or most any lights) (feel free to go look the existing wiring). You have short grounds that attach to the core support.
Posts above suggesting AAW factory fit harnesses mean upgraded reproductions of factory harnesses. What you're talking about is a new complete, partially terminated harness that's quite different for someone with no electrical understanding or skills.

Chances are you're better off fixing the existing harness for a while, learning some stuff and replace it if needed later on.

[Ewr101]

Well since nothing is wrong with the existing harness, I don't need to repair it at all. I Just want it replaced cause it's 40 years old and uses glass fuses. I'll just get the harness, go slow and get it done...

[franken]

You might be better off checking brakes, steering, and ball joints. These are moving/wear parts needing (and usually not getting) attention every few months.
Randomly replacing parts based on age is not a great approach.
Try checking steering wheel play, drift while driving, or a fun brake lockup test on a deserted bit of road.
Give it a complete tuneup (not gong into it), fluid change (engine, trans, diff, PS, brake fluid), and lube.

[Ewr101]

That's the awesome part about this thing, the PO's dad had it mildly restored when he bought it in the early 90's. It's already got headers, HEI and internally regulated alternator. When he died, the son inherited it and just tinkered with it and drove it on the weekends. It hasn't even had a top on it in over a decade! Being an airline pilot he was very meticulous about maintenance. I have receipts for regular full services going 15 years back. I just want to start bringing into the next century. I appreciate your advice and taking the time to answer.

[jaros44sr]

Nice truck.....

I agree with you, wiring should be replaced, i was quite surprised at the condition of mine after i got into it. Wiring becomes stiff and brittle with age, and some of my circuits were even melted together, but looked fine from the condition of the tape wrap on the outside.

It shouldn t be that hard to do, as the fuse block has one screw that keeps it together. Everything else just has push in connecters

We ve got your back, if you run into any problems....

Start with the engine side of the firewall, to get your feet wet, only has two harnesses. Engine and headlight

[Orangetonicclicc]

You have 5-6 major grounds. 1st and most important (1) Battery to Engine (2) Engine to frame (3) Front Clip/radiator support to frame (4) Cab to frame (5) Bed to frame. Additional smaller Guage wires will help like a couple off the valve covers going inside the cab, some on the head light and tailight housing to the body now that it is grounded to the frame. I made mine myself. Use a nice size gauge for frame to body applications with a big crimped from work. Just be sure to ground in clean unpainted rust free metal. Ground is the easier most critical thing when it comes to wiring. I bought the painless and I'm currently wiring mine as we speak. If I could go back, I would have went with American Wire. The Dakota Digital Dash Instruments makes it easier but it pricey! But well worth the cash! Good luck bro!

[Ewr101]

Cool. Thanks, I don't think it'll be too difficult once I have it all in front of me.One last thing.... Is there some sort of dielectric grease or paste that should be "painted" on two mating surfaces to protect the connection of the ground to the frame, block or body that will not only keep the connection clean and protected but also keep rust from forming?

[Orangetonicclicc]

Yes you can put some sort of dielectric on it and after that just paint over the uncovered surface to eliminate rust...

[jaros44sr]

One last bit of advice( as mentioned by Fitz on the pickup message board) Pick up an assembly manual, and copy the schmatic down in the electrical section