I am about to put my wiring harness back in a recently painted engine bay. What is the proper way to prepare spots that will be a grounding point? If anyone has a picture of 2, that would be great. I have gone thru the search but did not find anything specific. Thanks for your help.

Skip

Grounds should be bare metal to bare metal. Take the paint off a small spot, the size of the washer that will interface with the body. Attach the ground wire connector, lock washer and bolt... Then you can use a dielectric grease to coat the assembly, or even spray a small spot of paint over the top..

FWIW,

Carl B.

Skip;

Not too much to it, really.

Two types of grounding points; first is the coarse sheet metal screw and second the threaded screw. With the second, make sure you run a tap to clean up the threads so that there isn't any corrosion there. On the sheet metal screw, it will probably cut new path to the metal so it will be ok. A dash of electrical lube won't hurt when you put in the screw.

That's the "thread" portion.

Now for the "contact" portion.

On both types, as far as the surrounding metal, take a moment to look at the size of the connector you will be holding in place with the screw. While the ideal is to make sure you have 100 contact for the connector to the base metal, there is a big problem in that there is a very good possibility that part of the metal you expose will NOT be properly covered by the connector and therefore protected from the elements. So, with the connector's surface area in mind, clean off the area around the screw hole only as far as "half" the connector's contact area. Feather out the surrounding paint to maximize the contact to the metal. Again, a dash of electrical lube to prevent corrosion is a good idea.

Use new screws, or at least remove any corrosion or paint from them that would interfere in establishing a good contact. Same goes for the connectors. Make sure the surfaces are clean. One note, it isn't always necessary to use sand paper or a file. In fact, in some cases this would be advised AGAINST. The reason being that some connectors have plating that helps with the electrical conductivity of the connection. So, rather than pull out a file or a piece of sand paper (although this works and it is what many of us have done for years), get a brass wire brush. This is usually stiff enough to remove corrosion, yet gentle enough that it won't remove plating.

When you attach the screw, make sure you apply sufficient torque to flatten any lock washers you may use, but you don't need to use a torque wrench.

FWIW

E

When connecting a ground point of the wiring loom to the chassis, use star washers instead of spring as they "bite" the sheet metal to form a good contact patch.

Thanks for the responses. I didn't know how much paint I needed to take off. I will take a look at the star washers.

Gee them kiwis got good ideas (star washer) for people that are standing upside down but their sinks swirl the wrong way.