Drivers Shock Tower Ground Block

This is a ground that almost none of the other grounding writeups even mentions. If you look directly at the top of the drivers shock tower near the area where the trailing coil is mounted you should find a white connector seemingly plugged into nowhere on the inner side of the tower. Leading to this connector is a thick bundle of black ground wires. This connection grounds systems throughout the car yet is often overlooked because most don't even know it exists. Repairing this ground is simple can cure multiple issues (particularly with in-dash circuits).

This image shows the ground connector between the trailing coil and shock tower:

To access this ground you will probably want to remove the trailing ignition coil for space. With the trailing coil out of the way, the connector can be disconnected. Now you will see that the connector plugs into a large copper grounding block covered in spade connectors. That block is held onto the shock tower by a single M6x1.0 bolt. Remove that bolt and then remove the ground block.

The block is made of copper and can thus be easily cleaned on a wire wheel mounted on a drill or grinder. Do be careful since more then once I have experienced the wire wheel catching on the block and flinging it towards my face. Generally this is not fun. Once the bock is shiny, set it aside and turn your attention to the car. Chase the threads in the shock tower with a tap and clean the area around the hole down to bare metal with a wire brush.

Contact cleaner is the preferred method of cleaning the harness connection but be aware that some contact cleaners destroy plastic. Make sure to read the instructions. Liberally soak the connectors in cleaner and then blow dry after 30 seconds or so. Repeat this several times in about 10 minutes to try and dissolve all the crud and corrosion. Contact cleaner is nasty stuff so keep it out of your eyes when you blow off the connector. Most of the time the wiring here is in good shape so all that's required is a cleaning. If you have damaged connections then the offending spade will need to be pulled out of the connector, recrimped and reinserted. Lacking the special crimper required, you may simply want to separate the damaged wire from the harness and secure to the ground block mounting bolt with a ring terminal.

Now that everything is clean, you can reassemble the ground. Coat a new stainless steel M6x1.0 bolt liberally with dielectric grease. Cover the copper ground block with the same grease and use the bolt to secure the ground block to the shock tower. Make sure that plenty of grease got between the block and tower. Squeeze grease into every contact on the harness, packing it in tightly with your finger. Reconnect the harness and make sure it is latched on tightly.

Reinstall the trailing coil if you removed it. Remember to use antiseize on the bolts, and dielectric grease on all connectors (especially the plug wire boots).