Stock Cluster to a Rally Gauge Cluster

Short answer: A 1967 Rally Gauge cluster is NOT a drop-in for the idiot-light cluster — the connector pin-out is completely different, and the volt (ALT) gauge needs two heavier wires the idiot-light harness doesn’t have. You can re-pin the existing connector and add wiring (Option II below), or replace both harnesses (Option I). You’ll also need gauge-type oil-pressure and coolant-temperature sending units. Budget a full weekend. (Verified using two bone-stock 1967 Firebirds; originally by Tony, converted by Al.)

Stock (idiot-light) cluster — 12-pin connector (pin numbers are molded into the connector; ordering is 1–6 top row, 12–7 bottom row):

Stock Cluster Connector Pin-Out (Idiot Lights)
Pin Wire Color Usage
1 Light Tan Fuel Gauge
2 Green (2 wires) Water Temp Light
3 Gray Illumination Lights
4–6 N/A —
7 Pink (2 wires) Ground
8 Blue/White stripe Oil Pressure Light
9 Light Blue Left Turn Light
10 Dark Tan Brake Light
11 Brown Generator Light
12 Medium Blue Right Turn Light

The TEMP, OIL, GEN, and BRAKE wires connect under the hood through two 10-pin firewall connectors (just below/right of the brake master cylinder — facing the firewall, left = Engine Harness, right = Forward Lamp Harness):

Engine Harness        Forward Lamp Harness
+---+---+             +---+---+
|   | * | Dark Tan    |   |   |
+---+---+             +---+---+
|   |   |             |   |   |
+---+---+             +---+---+
| * |   | Dark Green  |   |   |
+---+---+             +---+---+
| * |   | Dark Blue   |   | * | Brown
+---+---+             +---+---+
|   |   |             |   |   |
+---+---+             +---+---+
  • Dark Tan to the brake master-cylinder pressure switch (BRAKE light on low pressure).
  • Dark Green to the coolant temperature switch (TEMP light above ~210°).
  • Dark Blue to the oil pressure switch (OIL light on low pressure).
  • Brown to the voltage regulator (GEN light on low output).
Why pin 2 has two green wires: turning the key to RUN (engine off) naturally lights OIL and GEN so you can verify those circuits. TEMP can’t self-test that way, so GM added a second green wire from the ignition switch that lights the TEMP bulb in the START position — a bulb-test “cheat” (it does not verify the temp switch or its wiring).

Rally Gauge cluster — 12-pin connector (same connector body, different pin-out):

Rally Gauge Cluster Connector Pin-Out
Pin Wire Color Usage
1 Blue/White stripe Oil Pressure Gauge
2 Green Water Temp Gauge
3 Light Tan Fuel Gauge
4 Gray Illumination Lights
5 N/A —
6 Gray Illumination Lights
7 Light Blue Left Turn Light
8 Dark Tan Brake Light
9 Medium Blue Right Turn Light
10 Pink (2 wires) Ground — but see correction below: actually +12VDC
11 White Volt Gauge
12 Black Volt Gauge

Firewall connector positions/colors for the Rally cluster:

Engine Harness        Forward Lamp Harness
+---+---+             +---+---+
|   | * | Dark Tan    |   |   |
+---+---+             +---+---+
|   |   |             |   |   |
+---+---+             +---+---+
| * |   | Dark Green  |   |   |
+---+---+             +---+---+
| * |   | Dark Blue   |   | * | Brown
+---+---+             +---+---+
|   |   |             | * | * | Black (L) / Black-White stripe (R)
+---+---+             +---+---+

The BLACK and BLACK-with-WHITE-stripe wires feed the ALT gauge and are a heavier gauge (higher current). The Black/White-stripe wire ties via a fuse link to the power-distribution splice near the voltage regulator and lands on the cluster’s White wire (pin 11); the Black wire ties via a fuse link to the junction block by the battery and lands on the cluster’s Black wire (pin 12).

Sending units needed (gauge-type):

Gauge Sending Units
Sending Unit GM p/n Classic Industries Niehoff / Borg Warner
Water Temp 12334869 ($17.43) G1872 ($17.68) DR134A ($5.33)
Oil Pressure 14039612 ($57.00) — DR135T ($17.22)

Option I — Replace the harnesses (easiest, costly): Classic Industries and Year One sell “for Rally Gauge cluster” harnesses. Replace both the Forward Lamp harness (~$199) and the Instrument Panel harness (~$399). No rewiring — just remove the old and fit the new.

Option II — Modify existing harnesses (affordable). The Rally cluster needs three wires the stock one lacks (a Black, a White, and a second Gray) and does not use the Brown (generator) wire. Steps:

  1. Print both connector pin-outs; disconnect/remove the battery; replace the cluster bulbs while accessible.
  2. Remove the stock cluster, then pull every wire/pin from the connector — slip a tiny flat screwdriver between the wire and the connector center to release each pin’s tab.
  3. Clip and tape off the extra Green wire (the one to the ignition switch — the START-position bulb test; not needed).
  4. Remove the Brown wire and splice it (with its pin) into the Gray wire to supply the Rally cluster’s second Gray (illumination); leave ~6″ of wire.
  5. Reinsert all wires into the connector per the Rally pin-out (your Brown is now one of the two Grays).

Volt-gauge wiring (the gauge stays dead until you add two wires; connector pins are scarce, so wire it directly to the gauge):

  1. Use ~20 ft of exterior-grade 2-conductor cord (Black/White, heavy enough for 120V). Attach round eyelets and fasten White to the left screw and Black to the right screw on the back of the cluster (at the volt gauge).
  2. Drill a firewall hole (above the fuse block), file it smooth, install a grommet.
  3. Fish the cord through (a little water-soluble lube helps) and up the left fender alongside the forward lamp harness to the voltage regulator; expose the two wires.
  4. Connect the White wire via an orange fuse link to the power-distribution splice near the voltage regulator (solder both joints).
  5. Route the Black wire along the radiator support to the battery power-junction block.
  6. Connect the Black wire via the second orange fuse link (with an eyelet) to the power-junction block.
  7. Reinstall the battery and test.

Member corrections & tips:

  • Pin 10 (pink) is +12VDC, not ground — the cluster grounds through the speedo-cable shield. Add a ground wire from the speedo housing to bare metal on the column.
  • You may not need to cut the Brown (generator) wire at all — the Rally cluster’s circuit card has a built-in jumper between pin 4 and pin 6 for illumination, so just tape off the unused Brown wire.
  • Use a proper connector-pin removal tool (~$10) rather than a screwdriver to avoid damaging pins/connector. Don’t cut unused pins — heat-shrink and tape them back.

1968 note: the 1968 Rally gauge uses GM circuit numbers — 8=illumination, 14=left signal, 15=right signal, 30=fuel sender, 31=oil pressure, 33=brake warning, 35=water temp, 39=ign(batt), 105=ammeter(batt), 106=ammeter(gen/alt). Connector positions: pins 1/3 jumpered to circuit 8, pin 4=30, pin 5=35, pin 6=31, pin 7=14, pin 8=33, pin 9=15, pin 10=39, pin 11=105, pin 12=106. For 1968 (and 1967) the member stresses all three harnesses must be changed — you cannot just change pin locations.

1968 Rally gauge circuit board diagram
1968 Rally gauge circuit-board diagram (from the 1968 Diagnostics service manual).

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Content last modified: June 13, 2026 at 10:06 am

Categories: Interior - All, Interior - Dash and Instruments

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