Last update: Oct 9 2016


This page describes the additional wiring added to support the new 12V components as well as the high voltage accessories.


Wiring Diagram

The AUX IG RELAY provides 12V power when the ignition switch is turned on. It is redundant to the car's ignition relay to avoid taxing any existing circuits.

The DC-DC converter input includes a diode and inductor to protect it from voltage sags and oscillations, respectively. The diode idea is from EVTV. The inductor is recommended in the Evnetics FAQ "Why does the fuse to my DC/DC converter keep blowing whenever I accelerate?"

The high voltage circuits, except for the controller, are controlled Gigavac P105 contactors.

Fuse Box

Many of the new components are contained in an auxiliary fuse box I added to the right side of the engine bay, where the air intake was.

Aux Fuse Box Aux Fuse Box Aux Fuse Box Aux Fuse Box

The 12V fuses and relays are plugged into a fuse and relay block called the Cooper Bussmann Rear Terminal Mini Fuse & Relay, purchased from Waytek Wire. I'll rarely be submarining, so no waterproofing seals or cover.

Cooper Bussmann 15303 Cooper Bussmann 15303 Cooper Bussmann 15303

The fuses and relays attach to the wires using Delphi Metri-Pack 280 series female terminals, so a crimper is needed. The GM Delphi Weatherpack Crimper Tool is relatively inexpensive and works fine.

Terminal Crimper

For making connections, I attached six 6-pole Wago Lever Nuts to the sides of the fuse and relay block using heavy duty double stick tape. Two are for unswitched power, two for switched power, and two for ground. These devices are easy to use and compact. Perfect for fixing mistakes and changing your mind.

Wago Lever-Nut

Part Numbers

EnclosureHammond Manufacturing 1444-10825 and 1434-108
12V fuse and relay blockCooper Bussmann 15303-4-0-4
12V mini fuse 5AWaytek Wire 46261
12V mini fuse 10AWaytek Wire 46263
12V micro relaySong Chuan 301-1A-C-R1-U03-12VDC
High voltage diodeSTMicroelectronics STTH200W06TV1
High voltage fuse 1/4" x 1-1/4" blockCooper Bussmann BK/S-8301-3-R
High voltage fuse 1/4" x 1-1/4" blockCooper Bussmann BK/S-8301-1-R
High voltage fuse 1/4" x 1-1/4" 30A (heat, A/C)Littelfuse 0505030.MXP
High voltage fuse 1/4" x 1-1/4" 10A (DC-DC)Littelfuse 0505010.MXP
High voltage fuse 1/4" x 1-1/4" 315mA (JLD404)Littelfuse 0508.315MXP
High voltage inductorBourns 1130-101K-RC
High voltage contactor 50AGigavac P105
Junction blockVTE 77025N02
Spacers under relay blockEagle Plastic Devices 561-kSP166
Splicing connector, 5 conductorWago Lever-Nut 222-415
Solid State RelayCrydom DC400D20

Ignition Switch Power

The AUX IG RELAY coil is fed by the vehicle speed sensor power wire, which is a convenient source of ignition switched power near the center of the fire wall. The VSS connector B17 color is gray in the service manual, but actually black in the car. Very confusing because it is right next to another gray connector with the same number of poles (connector B128).

The DC-DC output relay coil is powered by a different ignition switched source. Connector F60 is located conveniently close to the 12V battery, where the DC-DC is located. Pin F60-4 originally provided power to the ignition coils.