The Stovebolt Site Forums The Shop Area The Electrical Bay Big truck grounds

Still working on my GMC 860 and figured since it's going to rain all day, I will spend the day in the shop and get back to work on some electrical. When I took over this project, aside from the battery cables there wasn't a wire on it. The previous owner had already removed it all. I had a harness made for the truck but there was nothing provided in the way of ground wires and nothing in their minimal diagrams. The neg cable from the battery connects to the starter on the 6-71 DD. I kmow I need to ground the cab and the frame and may even need to run a ground to the cowl as it is supported by rubber mounts to take the pounding of the road.
I did do a little searching and got a few ideas but since this is a little different vehicle than what's usually dicussed here I am throwing this out to the experts for suggestions on wire size/type and location ideas. Not concerned with factory look.
The only other thing worth mentioning is the taillights will be LED and from what I read, they will require additional grounds.
Thanks for any tips you may have.
Billy

Hy Bill Marlow, firstly I must say how envious I am that you have that truck to work on and I'm extremely impressed with the work you have done so far! As I'm sure you are aware, is it not possible to have too many ground wires. Many of the fixes for today's vehicles with electrical gremlins involve "add ground wire". That said I would ground engine to frame, frame to cab, doors to cab, aluminum to steel, fenders to cab/frame, try not to put too many connections in the same place that will provide more paths to ground rather than funneling a lot through one connection. Connections that are clean down to bare metal when made and then coated to prevent corrosion are best. Good luck with your grounding project!

Physical grounds have always been a problem. For the past 30 years or so, truck manufacturers have been running 2 wires to each light. International uses a stainless steel bolt through the firewall on their 9000 series. The bolt is first tightened to the firewall and then all the grounds are attached to it. We run a 4/0 from the batteries to the starter solenoid and another 4/0 from the batteries to the starter mounting. We run a 10 gauge wire from the alternator + to the starter and also ground the alternator to the starter. A strap goes from the starter to the common ground on the firewall. 40 years ago lights were a problem. Especially after truck manufacturers when from positive to negative ground. We now use Trucklite and a few Grote LED lights and stay away from cheap no-name LED and we have almost zero light problems. We use Trucklite grease on all plugs.

http://www.ryderfleetproducts.com/r...uct&gclid=COjO9KedscYCFQgtaQodKWQN3w

I don't even have a 67 or an 1157 bulb in the parts room any more.

Thanks Bob for the kind words, I would feel a whole lot better about "the work I have done" if it wasn't year 5+ on the project and I had hoped to have it done in 3 tops. I am still fumbling around, sure wish I had a Ken Crenwelge living next door!!
I spent sometime on Saturday in the shop and managed to run a few ground on the truck while it rained 2 1/2"! Turned out fairly neat and tidy. Sure and thankful for a nice dry area to work on my truck.
Ken, great points. I will use it for a guide as I continue on with my electrical potion of this project.
I did come to realize that a couple of the circuit breakers are bad. Ken are these readily available?
http://s1366.photobucket.com/user/M...g7_zpsa7106415.jpg.html?sort=6&o=159

Thank you both for your responses.

Billy

Hy Bill Marlow, those circuit breakers in your picture are standard self-reseting circuit breakers without a mounting bracket attached, Cole Hersee 30056 type 1 many amperages are available, hope that helps.

hey Bill,


What a nice big rig you have, no i'm not one of the 3 bears ....
grounds are nice to have and having an extra here and there can't hurt. just so long as you know where they are.

i made my own harness from scratch. i added many new modern switches and routed wires to hind them as best possible but still allowed access.

if you have an 'auto stereo'' shop close by you may ask them if they have any scrap power wire. it'll come in various colors and is usually multi stranded. by auto stereo standards for high -fi boom box stuff is about twice to 3x the number of strands compared to a flaps wire spool. ......... and possible cheaper too. you can get the solders copper ends for the big 2 and 4 ot. stuff and solder it after crimping the connectors to the wire. 2 types of physical connections. crimped and soldered. throw some heat shrink over it and you good.

https://www.google.com/?gws_rd=ssl#q=automotive+anti+corrosion+paste

i would also use some anti corrosion paste over the connectors that are bolted to any frame. BE SURE you are down to BARE METAL when you bolt everything.

i run grounds::

frame to cab.
cab to bed
frame to engine.
frame to bed.
frame to gas tank make it long enough so if you have to drop the tank you have wire to the lower the tank down.
radiator frame to frame, i have a pusher fan.
frame to battery.

yeah i have a couple extra inside the cab for my instruments

keep up the grand work, we're watching