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1.4.3 PMU Outputs

Complete configuration of all 24 PMU outputs, load allocations, and combined output configurations.

PMU24 Output Configuration

25A High-Side Outputs (OUT1-OUT10)

Output Circuit Load Ground Control Type Notes
Out 1 [Available] - - - Freed — iBooster relocated to START+ Forward Bus
Out 2 [Available] - - - Freed — radiator fan relocated to START+ Forward Bus
Out 3 [Available] - - - Freed — radiator fan relocated
Out 4 [Available] - - - Freed — radiator fan relocated
Out 5 HVAC Blower Motor ~20A Restomod Air kit ground (verify on arrival) Auto (ignition ON) Restomod Air kit blower; draw verification ⚠️ TBD #146 — see HVAC System
Out 6 GMRS Radio (Midland G1) 15A Direct START battery- CONSTANT RF noise isolation
Out 7 Oil Cooler Fan ~15A Engine Bay Bus Stud 8 Auto (CAN temp) SPN 175 oil temp trigger
Out 8 PS Cooler Fan ~15A Engine Bay Bus Stud 8 180°F inline thermostat Mishimoto PS cooler fan; thermostat-switched on PS fluid temp (not engine coolant)
Out 9 Dakota Digital System ~25A Firewall Stud Bus T4-5 CONSTANT Cluster + 4 BIM modules; gauge power architecture (OUT9 vs Critical Cabin PDU) ⚠️ TBD #144
Out 10 [Available] - - - Freed — iBooster relocated to START+ Forward Bus

15A High-Side Outputs (OUT11-OUT16)

Output Circuit Load Ground Control Type Notes
Out 11 WS-51C Wiper Controller 15A Firewall Stud Bus T2 Auto (ignition ON) See Wipers
Out 12 [Available] - - - Future expansion (15A)
Out 13 Command Touch CT4 ~9A Firewall Stud Bus T1 CONSTANT Turn signals, headlights, hazards
Out 14 [Available] - - - Future expansion (15A)
Out 15 [Available] - - - (Was Winch Contactor Trigger — reallocated 2026-05-30 to BODY PDU CB43)
Out 16 [Available] - - - Freed — TCU relocated to START+ Forward Bus

7A High-Side Outputs (OUT17-OUT24)

Note: OUT17-24 are dual-purpose - configurable as 7A outputs OR 0-20V analog inputs. See PMU Inputs for analog input configuration.

Output Circuit Load Ground Control Type Notes
Out 17 A/C Clutch 3-5A Compressor clutch ground (Restomod Air kit — verify) Auto (A/C request) Request via Restomod Air control head → trinary → In 9 — see HVAC System
Out 18 Horn 5.4A Engine Bay Bus Stud 6 External input PIAA horns (2.7A × 2)
Out 19 [Available] - - - Freed — iBooster enable now on ignition bus
Out 20 STX Intercom ~5A Direct START battery- Auto (ignition ON) RF noise isolation
Out 21 Brake Lights ~3A SwitchPros Ground Bus External input Shared tail light ground
Out 22 Reverse Lights ~5A SwitchPros Ground Bus External input Maxbilt + Squadron Sport
Out 23 DRL/Parking Lights ~2.6A SwitchPros Ground Bus Auto (ignition) See DRL & Parking
Out 24 [Available] - - - Available for future expansion (7A)

Combined Outputs

The radiator fan (formerly OUT2+3+4) and iBooster main (formerly OUT1+10) were relocated to the START+ Forward Distribution Bus. No PMU outputs are currently combined; OUT1–4, OUT10, OUT15, OUT16, and OUT19 are now free (8 spare outputs). The combining rules below are retained for any future high-current output.

Combining Rules:

  • Only same-rated outputs can be combined (25A + 25A ✓, 25A + 15A ✗)
  • Outputs do NOT need to be adjacent - combine via external wiring at load
  • Thermal limits: Two adjacent 2.8mm terminals = 38A max @ 23°C, 32A @ 40°C for continuous loads
  • Non-adjacent terminals: Each rated 23A @ 40°C individually = 46A combined capacity (much better thermal performance)
  • Brief peak loads: Thermal derating less critical for loads <5 seconds (e.g., brake booster)
  • Load balancing: Avoid placing heavily loaded outputs adjacent to each other - use non-adjacent combining for high-current loads
  • Use proper terminal crimping and wire gauge to maximize current capacity

Thermal Analysis

High-Current Outputs (Thermal Concerns):

Outputs Load Terminal Rating Utilization @ 40°C Status Notes
OUT5 20A continuous 23A (single @ 40°C) 87% ✓ OK HVAC blower - now the largest continuous PMU load after fan/iBooster relocation
OUT11 15A continuous 19A (1.5mm terminal) 79% ✓ OK Wiper controller - avoid adjacent high-current load on OUT12

Installation Notes:

  • PMU thermal protection will shut down overloaded outputs
  • Monitor output temperatures during initial testing (PMU displays thermal status)
  • Non-adjacent combining recommended for all high-current loads (>30A) to maximize thermal margin
  • Continuous loads (HVAC, fans) require more conservative thermal margins than brief peaks

Grounding Architecture:

  • PMU uses high-side outputs (switches positive power to loads)
  • Each load grounds separately (chassis ground, battery ground, or ground bus)
  • Pin 25 is reference ground ONLY (<100mA logic/CAN reference)
  • Output current does NOT return through Pin 25 - returns through individual load grounds
  • See Grounding Architecture for load ground connections