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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 iBooster Main (combined) Combined Engine Bay Bus Stud 7 CONSTANT Combined with OUT10, 40A peak
Out 2 Radiator Fan (combined) Combined Fan housing → engine block PWM (CAN temp) Combined with OUT3+4, 53A max
Out 3 Radiator Fan (combined) Combined Fan housing → engine block PWM (CAN temp) Combined with OUT2+4
Out 4 Radiator Fan (combined) Combined Fan housing → engine block PWM (CAN temp) Combined with OUT2+3
Out 5 HVAC Blower Motor ~20A Factory HVAC ground Auto (ignition ON) 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 Auto (CAN temp) SPN 110 coolant temp trigger
Out 9 Dakota Digital System ~25A Firewall Stud Bus T4-5 CONSTANT Cluster + 4 BIM modules
Out 10 iBooster Main (combined) Combined Engine Bay Bus Stud 7 CONSTANT Combined with OUT1

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 Ham Radio (iCom IC-2730A) 13A Direct START battery- CONSTANT RF noise isolation
Out 13 Command Touch CT4 ~9A Firewall Stud Bus T1 CONSTANT Turn signals, headlights, hazards
Out 14 ADU7 Display ~2A A-pillar ground Auto (ignition ON) See ADU7 Display
Out 15 Winch Contactor Trigger 1A Via winch contactor Manual (dash rocker) Control signal only
Out 16 Turbolamik TCU 15A Engine bay ground bus CONSTANT 8HP70 transmission controller

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 Factory A/C ground Auto (A/C request) See HVAC System
Out 18 Horn 5.4A Engine Bay Bus Stud 6 External input PIAA horns (2.7A × 2)
Out 19 iBooster Ignition Signal ~5A Engine Bay Bus Stud 7 Auto (ignition RUN) Same ground as iBooster main
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 ~2A SwitchPros Ground Bus Auto (ignition) See DRL & Parking
Out 24 Ignition Authorize ~5A Via downstream loads PMU state machine Drives ECM ignition relay + supplies hardware crank chain (push button → brake → P/N → ER lockout → Cole Hersee). See Keyless Ignition

Combined Outputs

Radiator Fan (OUT2+3+4): GM Camaro electric fan, 53A @ full speed, 3×25A outputs paralleled = 75A capacity, PWM variable speed control

iBooster Main (OUT1+10): Bosch Gen 2, 40A peak, 2×25A outputs paralleled (non-adjacent) = 46A @ 40°C capacity, CONSTANT power

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
OUT1+10 40A peak (brief) 46A @ 40°C (non-adjacent)
50A @ 23°C		 87% @ 40°C peak
1% @ idle		 ✓ EXCELLENT iBooster - non-adjacent combining eliminates thermal concerns, 0.25A idle
OUT5 20A continuous 23A (single @ 40°C) 87% ✓ OK HVAC blower - relocated from OUT1, same thermal margin
OUT11 15A continuous 19A (1.5mm terminal) 79% ✓ OK Wiper controller - avoid adjacent to OUT12 if possible
OUT12 15A (if used) 19A (1.5mm terminal) 79% ✓ OK Available - avoid adjacent to OUT11 if possible

Installation Notes:

  • PMU thermal protection will shut down overloaded outputs
  • Monitor output temperatures during initial testing (PMU displays thermal status)
  • iBooster thermal design: Non-adjacent combining (OUT1+10) provides 46A @ 40°C capacity vs 40A peak load = 87% utilization ✓
  • 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

Thermal Analysis - iBooster Resolved

iBooster relocated from OUT5+6 (adjacent) to OUT1+10 (non-adjacent) per ECUMaster PMU24 manual Section 2.13:

- Non-adjacent 2.8mm terminals @ 40°C: 46A combined capacity (23A each)
- iBooster 40A peak: 87% utilization ✓ Excellent thermal margin
- Maximum physical separation eliminates adjacent terminal heating concerns
- HVAC blower relocated to OUT5 (single output, 87% utilization, unchanged)

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