What the pink wire does
The pink wire is a signal, not a power feed. It tells the Haltech fuse box when the ignition is on, and that switches on the main engine relays, which then power the ECU, injectors, coils and the other loads on the harness. Because it only triggers relays, it carries very little current, well under half an amp. There's no need for heavy wire, but the connection has to be solid.
Where to connect it
Find a terminal on the ignition switch that has 12V in both of these positions:
- Ignition on (run)
- Crank (start)
Test with a multimeter or test light in each key position before you connect anything. The terminal must also be dead with the key off, or the relays will stay on and flatten the battery.
Many ignition switches drop the accessory circuit while cranking, to free up current for the starter. If the pink wire is on accessory, the relays switch off the moment you turn the key to start. The ECU, fuel and spark all lose power, and the engine won't fire.
Quick checks if it won't start
- Measure the pink wire while cranking. It should hold close to battery voltage.
- Listen for the relays clicking on with the key and staying on through cranking.
- Check that the fuse box has its main battery feed, and that the fuse or circuit breaker on that feed is intact. Haltech's diagram for this harness allows a 75 A circuit breaker in place of a fuse, so if you want the diagram, ask us and we'll send it over with advice for your build.
For the rest of the power side, see power and ground wiring, the battery supply wires and the black battery ground. We also stock the 6-circuit Haltech fuse box for custom builds.
