Skip to content

1.7.6 Build Sheet — Controls, Recovery & Drivetrain

Workbench specs for the recovery and drivetrain harnesses: H6 ARB Compressor, H7 Winch Trigger, H8 Kilduff Shifter → TCU, and H9 TCU → Engine Bay.

LJ Tub Map — Controls, Recovery & Drivetrain routing (top-down): ARB compressor, winch contactor trigger, shifter, and TCU runs (H6–H9)

Top-down tub map of the controls/recovery/drivetrain harnesses. Diagram source: Jeep LJ Tub Map.drawio (page "Controls, Recovery & Drivetrain"); the image is regenerated from the draw.io file on each export.

Reading this sheet: Power = red, ground = black; CAN runs as a twisted pair; vendor-supplied harnesses (ARB, CH4X4, Kilduff/ZF) keep their shipped colors. See the Wire Color Convention. The H6 compressor motor pair is a power run and takes a red braided sleeve (blue tracer); the small-wire signal harnesses (H7, H9) use split loom — see Protective Sleeve & Tracers. Other protection standards by location are in Wire Protection Standards; system-wide context is in the Harness Inventory overview.

H6 — ARB Compressor Bundle

Previously numbered H8. Renumbered 2026-05-31.

Build: 4 conductors (2× 6 AWG motor + 2 signal) · ~10 ft · lug at SafetyHub, ring/spade at compressor · motor pair in red braided sleeve (blue tracer) · the two signal wires originate at SwitchPros, not SafetyHub.

Route: SafetyHub (passenger rear wheel well) → under cargo / under rear bench → under passenger seat (compressor mount)

Length: ~10 ft

Contains:

Wire Gauge Color Function Termination at SafetyHub Termination at compressor
Motor 1 power 6 AWG Red (per ARB) SafetyHub MIDI-1 (60A) → compressor motor 1 Lug to MIDI-1 output Compressor motor terminal
Motor 2 power 6 AWG Red (per ARB) SafetyHub MIDI-2 (60A) → compressor motor 2 Lug to MIDI-2 output Compressor motor terminal
Control signal 14 AWG Per SP pigtail SwitchPros OUT-11 → compressor control terminal (Comes from SwitchPros at firewall, not SafetyHub — runs separately or joins this bundle along common path) Compressor control terminal
Pressure switch 18 AWG Per SP pigtail ARB pressure switch (on manifold under passenger seat) → SwitchPros TRIGGER-3 (At firewall, not SafetyHub) Pressure switch normally-open contact

Connectors: Lug at SafetyHub side, ring/spade at compressor. ARB compressor manifold typically has a pigtail with its own connector.

Protection: Red braided expandable sleeve (blue tracer) over the 2× 6 AWG motor pair along the under-floor / under-seat run. Split loom for the control + pressure signal wires. P-clamps every 12–18".

Notes:

  • Motor 1 + motor 2 are 6 AWG (high current, brief peaks) — bundle as a pair
  • Control + pressure switch wires originate at SwitchPros at firewall, NOT SafetyHub — they run from firewall through cabin to under passenger seat
  • Could be merged into H6 if they share routing, or kept separate as "H6b ARB signal"

Optimization opportunity: Run the SwitchPros control + pressure switch wires through the cabin trunk to under passenger seat as part of H5 SwitchPros rear bundle (they're SP wires anyway), and split off at the compressor. Saves a separate harness — the only ARB-specific harness is the 2x 6 AWG motor cables from SafetyHub.

H7 — Winch Trigger Control (small wire)

Previously numbered H9. Renumbered 2026-05-31.

Build: 5 conductors (all 18 AWG) · ~3 ft (BODY PDU → dash) + ~13 ft (dash → contactor) · CH4X4 switch ships its own pigtail + cable kit · HDP24 at firewall.

Route: BODY PDU (firewall, cabin side) → dash switch (CH4X4 dual-momentary push) → HDP24 firewall pins 16/17 → winch contactor at front bumper

Length: ~3 ft (BODY PDU → dash) + ~13 ft (dash → contactor via engine bay)

Contains:

Wire Gauge Color Function Termination
Switch +12V supply 18 AWG Red BODY PDU CB43 (10A) → CH4X4 switch common Spade at BODY PDU, included pigtail at switch
IN trigger 18 AWG Per CH4X4 pigtail CH4X4 IN button → HDP24 pin 16 → contactor IN trigger Included pigtail at switch, HDP24 socket, ring/spade at contactor
OUT trigger 18 AWG Per CH4X4 pigtail CH4X4 OUT button → HDP24 pin 17 → contactor OUT trigger Included pigtail at switch, HDP24 socket, ring/spade at contactor
Illumination supply 18 AWG Per CH4X4 pigtail Dash illumination circuit Included pigtail at switch
Switch ground 18 AWG Black Switch common ground Chassis ground at dash

Connectors: CH4X4 includes its own connector + cable kit. HDP24-24-29 at firewall penetration. Ring/spade terminals at contactor.

Notes:

  • BODY PDU CB43 (10A, ~3 ft to dash) replaces the previously-planned SafetyHub ATC-1 (15A, ~13 ft from rear wheel well). The 18 AWG wire is properly sized for the ~3A trigger current; the prior 14 AWG / 15A spec was over-built and routed wastefully.
  • Switch is dual-momentary push (not a polarity-reversing rocker) — the WARN ZEON 10-S contactor handles polarity internally
  • Warn handheld remote wires in parallel at the contactor trigger terminals
  • SafetyHub ATC-1 slot freed for future use (recovery accessories etc.)

H8 — Kilduff Shifter to TCU

Previously numbered H10. Renumbered 2026-05-31.

Build: 1 multi-conductor proprietary harness (supplied with the Kilduff shifter kit) · ~3–5 ft · factory 8HP70 connectors · no fabrication required.

Route: Kilduff shifter in center console → straight down through trans tunnel → Turbolamik TCU mounted on 8HP70 mechatronic (transmission valve body)

Length: ~3–5 ft

Contains:

Wire Gauge Color Function Termination at shifter Termination at TCU
Shifter harness Proprietary multi-conductor (factory 8HP70 connector) Factory (Kilduff/ZF) All shifter signals (P/R/N/D, manual +/−, button states, illumination) Kilduff-supplied connector at shifter base Factory 8HP70 connector at TCU

Connectors:

  • Kilduff supplies the shifter end of the harness with their shifter kit
  • TCU end uses the factory 8HP70 mechatronic connector (Turbolamik TCU 2.0 mates to this)

Protection: Split loom through trans tunnel. The trans tunnel keeps the cable away from cabin contents and provides a clean straight run.

Notes:

  • TCU is mounted on the 8HP70 mechatronic (the trans valve body), not in cabin or engine bay — so this is a very short pull
  • No firewall penetration
  • No other H-series harnesses share this path — it's a single-purpose, self-contained run
  • Kilduff includes the wiring harness with the shifter kit — no separate fabrication required

See Transmission for shifter and TCU specs.

H9 — TCU to Engine Bay

Previously numbered H11. Renumbered 2026-05-31.

Build: 6 conductors (incl. one twisted CAN pair) · 3–4 ft · TCU connector at one end, individual terminations in engine bay · split loom + heat sleeve at engine-bay entry.

Route: Turbolamik TCU on 8HP70 mechatronic → up through trans tunnel forward → engine bay (PMU + J1939 tap + starter P/N relay)

Length: 3–4 ft

Contains:

Wire Gauge Color Function Source Destination
TCU power feed 14 AWG Red PMU OUT16 (CONSTANT, 15A) → TCU power input PMU OUT16 (engine bay) TCU power terminal
J1939 CAN High Twisted pair Twisted pair (CAN) Shared J1939 bus tap (same tap as PMU, Dakota Digital BIM-01-2) CAN bus tap point TCU CAN-H
J1939 CAN Low Twisted pair (paired with CAN High) Twisted pair (CAN) Shared J1939 bus tap CAN bus tap point TCU CAN-L
Aux out (Reverse) 18 AWG Builder's choice TCU aux output: 12V when shifter in R → PMU In 3 (drives PMU OUT22 reverse lights) TCU aux Reverse pin PMU In 3
Aux out (P/N) 18 AWG Builder's choice TCU aux output: 12V when shifter in P or N → starter P/N interlock relay coil TCU aux P/N pin Starter P/N interlock relay coil+
Brake input 18 AWG Builder's choice Dedicated brake-pedal signal for unlock-from-Park (separate from PMU In 2 tap) — crosses firewall via HDP24 Cabin brake pedal switch TCU brake input pin
TCU ground 14 AWG Black TCU ground return TCU ground terminal Engine bay ground bus

Connectors:

  • TCU end: Turbolamik TCU's connector (depends on TCU model — 2.0 typically uses a small Deutsch DT or similar)
  • Engine bay ends: Each wire terminates at its destination (PMU spade/screw terminal, J1939 splice, relay coil terminal, ground bus stud)

Protection: Split loom from TCU through trans tunnel up to engine bay. Heat sleeve where it enters engine bay zone (>12" from exhaust).

Notes:

  • Engine-bay endpoints need no firewall penetration; the one exception is the brake-switch input below, which originates at the cabin brake pedal switch
  • J1939 CAN tap is shared with PMU and Dakota Digital BIM-01-2 — the TCU is a third node on the same bus (just adds a splice at the existing tap point)
  • Brake switch input to TCU (for unlock-from-Park): dedicated wire (decided 2026-06-03). A separate 18 AWG conductor runs from the cabin brake pedal switch through the firewall (HDP24, dedicated pin) to the TCU brake input — not a shared tap off the PMU In 2 feed. A dedicated wire keeps the TCU and PMU brake-sense paths electrically independent (a fault or load on one cannot disturb the other) at the cost of one added HDP24 contact
  • TCU is one of three controllers tightly coupled to the engine bay: PMU24 (mounted on firewall), Dakota Digital BIM modules (on HDPE panel cabin side), and TCU (mounted on transmission). All share the J1939 CAN bus.

See Transmission and PMU Outputs for related details.