wiring advice

[tnt_motorsports]

Good day All
I'm looking for some input on the wiring for my MK3. The kit I purchased came with an aftermarket wire harness. It is not the RF one, which is fine, and I think it will work out fine. As noted in my build thread, I have installed the fuse panel and started to route the main harness. I have routed the front harness for the head lights, turn signals and fan wire. One thing I noticed is this kit does not include a ground wire for the front harness. Instead, it has separate wires in the kit that appear to be for individual grounds for each light. I have thought about this, and I am not a fan of separate grounds for the lights. My theory is too many grounds will end up being a problem at some point.

So now my question, does anyone see an issue if I run a wire in the harness that is a ground and then ground it as shown in the FFR wire harness instructions in the foot box? I would run a common wire in the harness with branches off for each of the lights. I would solder and shrink wrap the connections. I would also do the same thing for the rear harness when the time comes and tie the grounds together into one connection in the footbox.

For context, I have been using a combination of the MK3, MK4 and wire harness instructions to navigate my way here.


Thanks in advance for this wonderful community that keeps me moving and motivated!

Todd

[JMD]

I don’t think doing it the way you describe would cause any problems, but it is good practice to give your harness multiple paths to ground. I used the grounds in my RF harness but also connected the main ground in the front harness to part of the frame as a redundancy. Too many individual grounds can be a headache, but a single point of failure that affects your entire front harness can be a problem as well. The best of both worlds is connect everything to a good common ground that itself has multiple paths to ground.

[rich grsc]

Good day All
I'm looking for some input on the wiring for my MK3. The kit I purchased came with an aftermarket wire harness. It is not the RF one, which is fine, and I think it will work out fine. As noted in my build thread, I have installed the fuse panel and started to route the main harness. I have routed the front harness for the head lights, turn signals and fan wire. One thing I noticed is this kit does not include a ground wire for the front harness. Instead, it has separate wires in the kit that appear to be for individual grounds for each light. I have thought about this, and I am not a fan of separate grounds for the lights. My theory is too many grounds will end up being a problem at some point.

So now my question, does anyone see an issue if I run a wire in the harness that is a ground and then ground it as shown in the FFR wire harness instructions in the foot box? I would run a common wire in the harness with branches off for each of the lights. I would solder and shrink wrap the connections. I would also do the same thing for the rear harness when the time comes and tie the grounds together into one connection in the footbox.

For context, I have been using a combination of the MK3, MK4 and wire harness instructions to navigate my way here.


Thanks in advance for this wonderful community that keeps me moving and motivated!

Todd

No you are incorrect, multiple grounds are just fine. In fact, it is a much preferred method.

[Nigel Allen]

Good question to ask. Multiple ground points are fine. It is just the same as your daily driver is built. Do them properly and they are never likely to be a problem. If you are really concerned just make the ground points where they will be accessible once the car is fully constructed.

Cheers,

Nigel

[edwardb]

As a certain major contributor to this forum (aka Mr. Kleiner) told me some years ago: "Ground is ground is ground." For our purposes on these builds, multiple grounds aren't just OK they're preferred.

[cdurbin328]

I used a small ground bus bar from Ace Hardware for my grounds.
I mounted it to the frame under the battery. Ran one lead from the negative battery post and then ran all of my grounds back to the bus bar.
216068

[lewma]

I used a small ground bus bar from Ace Hardware for my grounds.
I mounted it to the frame under the battery. Ran one lead from the negative battery post and then ran all of my grounds back to the bus bar.
216068

I did a complete custom harness on my coupe build and used this same approach. all my grounds come back to the bus bar and are grounded there

[rich grsc]

I used a small ground bus bar from Ace Hardware for my grounds.
I mounted it to the frame under the battery. Ran one lead from the negative battery post and then ran all of my grounds back to the bus bar.
216068
Multiple possible failure points with each wire ran, and additional wire resistance. The frame is an excellent grounding source, that is why the battery is grounded to the frame.

[OB6]

I used a custom harness so I could locate the fuse panel in the trunk. This required me to figure out my approach for grounds. I welded 1/4" stainless studs to each corner of the chassis, one under the trunk, and a nut on the 2" tube behind the dash. Where possible, I used the closest ground location for each load, careful not to turn each stud into a Christmas tree. I have two Blueseas Systems bus bars... a small one in the trunk and a 150a unit behind the dash. The dash bus bar is connected with a 4 gauge wire to the welded nut on the 2" tube, and the trunk bus bar is connected to the closest grounding stud (i.e. under the trunk). The engine is grounded to two locations on the chassis, and the battery is grounded at the location most people use with the Breeze battery box. I avoided splicing into a common ground wire and instead chose to use home runs to the ground locations.

Time will tell, but I'm pretty happy with how it worked out. I know where all the ground locations are, and they're easy to access.

216070