Overthinking Grounds…

I read a bunch of threads on grounds, read instructions and the FSM, reviewed my pictures, and checked out my JC wiring.

I have the original ground cable from the engine block to the mounting bracket/frame. I cleaned off paint from the surfaces of the engine and the frame and put the cable contacting the engine and frame, not on the outside of the bolt.

The original cable looks a little light. Do I need to upgrade? I have a 1 ga braided ground line (it is huge) that I could use in place. Is it overkill to put it directly next to the engine block and frame? Would it conduct well enough if I bolted it on the surface?

Next question is the battery ground. I have a 2 ga positive from the battery to the starter. My ground (to the engine block or frame or starter mount) is 4 ga. Shouldn’t they match?

Thanks in advance.

 

The engine to frame ground wire if in good condition should be fine. I used a ground strap kit from painless wiring and grounded the grill and body to the frame and the body to engine as well. I dont know if my original battery cables were original or replaced but i think they were both 2 gauge.

 

If some is good, more is better. Can't hurt to have another ground or a larger ground.

 

I took an old jumper cable and ran hot to alternator, ground to the firewall battery tray then to intake.
Then I have a large positive to the starter.
I have nothing but the stop light switch on the frame (non grounded two pin inline switch) . The tail lights and trailer plug ground to the tub.

 

Grounds are your friend. I have neutral to the block, a large ground block to frame, large ground block to firewall. I go from the fire wall to the wiper motor, to the tail lights & gas tank.

 

The tail and reverse lights ground to the tub through the housing correct? Seems strange to me because the housing is painted and the bolts look like black oxide.

 

I'd think you need to consider a few things - first, for short runs, connection resistance seems certain to be far greater than the wire resistance for a large short jumper. Second, the change in resistance due to wire size is minuscule over short distances. Not something I'd put a lot of effort into.

I would make sure the connections are good, bright metal against bright metal. Clean, new bolt. I would use a new shakeproof washer at each connection. Dielectric grease like Howard mentions would be good to prevent future corrosion, but does not change the quality of the connection. Make sure the attaching bolts are good and tight - look up the appropriate torque for that size connection if you are unsure.

The steel body is one big conductor, and your lights and such need to connect to it as described above. Usually the ground cable goes to the engine, and there is a jumper between the engine and the frame. The starter motor is the main user of current, and it depends on both the positive and the negative battery cable. Many applications have a ground jumper from the negative batter terminal to the body steel - good to add if it's not there.

 

This is where a new shakeproof lock washer will help you. Likely the original nuts had captured shakeproof lock washers that cut through the paint and made a good connection with the body steel. Add a second shakeproof washer between the bucket and the body if you worry about conducting through the bolt. And dielectric grease.

I don't have a loose factory tail light bucket to look at, but I thought they have bright plated studs (Cad? Zinc?) that are crimped into the painted housing. The backup light buckets are chrome plated.

 

Backup on top, tail below. You are correct about the studs. The tail light housing is painted - I didn’t know if the back of the housing needed contact. The bedliner may be a problem, so I will sand that down a bit. Thanks!

 

Perhaps not in your case but rust around those tub "grounded" tail lights is a really common problem. I do run dedicated ground wires to a frame connection and from there directly to the battery whenever I'm working on those. As Howard noted, use dielectric grease on all those connections. And I'm a big believer in overkill on battery cables. I make those out of 1-0 or 2-0 welding cable with crimped/soldered/heat shrunk terminals.

 

Run the ground off the post like this?

 

There is no negative terminal on my starter, so am I correct to assume I can connect the battery negative to a mounting post on the starter?

I can't find a distinction between shakeproof washer, star washer, and external tooth washer. Same thing?

 

Yep and yep. The starter mounting bolt is the most direct path you have for the largest amp draw with the possible exception of a winch. IMO, much better than the front of the block.

 

Correct. And a constant source of woe.

 

thank you @duffer for that. Was thinking yet another washer/tech thin I had to learn.