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2.3 HVAC System

Type: Custom Electronic A/C + Heat System

Model: Restomod Air custom kit — configuration ⚠️ TBD #146 (confirm against order)

Manufacturer: Restomod Air

Mounting: Under-dash (replaces factory TJ HVAC assembly)

Power Source: PMU OUT5 (blower motor), OUT17 (A/C clutch)

Control: Restomod Air electronic control head

Overview

Custom Restomod Air electronic HVAC system (on order) replaces the factory 2005 TJ HVAC.1 Restomod Air kits are fully electronic — mode and blend doors are servo-driven from the control head — so the factory vacuum mode doors, cable blend door, and dash control panel are all deleted.2 This removes the build's only vacuum consumer: no vacuum supply from the R2.8 is required (the diesel makes minimal manifold vacuum anyway, and braking is already vacuum-independent — see iBooster).

PMU Integration

Circuit PMU Load Control Notes
Blower Motor OUT5 (25A) ⚠️ TBD #146 — verify kit blower draw ≤25A Auto (ignition ON) Blower speed controlled by Restomod Air control head, not PMU
A/C Clutch OUT17 (7A) 3-5A In 9 trigger Restomod Air control head compressor request → trinary switch → PMU In 9 (⚠️ TBD #146 — verify wire ID against kit diagram on arrival)

See PMU Outputs for complete configuration.

A/C Request Circuit (PMU In 9)

The Restomod Air control head generates the A/C request: when A/C is commanded, its compressor-engage output goes to 12V. That output routes through the kit's trinary pressure switch (30 psi low-pressure cutout, 406 psi high-pressure cutout)3 and then to PMU In 9, so the PMU only sees a request when refrigerant pressure is in the safe range. PMU logic then drives OUT17 → compressor clutch.

The trinary switch's third function (electric fan request at 254 psi) is not wired — radiator fan control is handled by the dedicated fan controller with its own coolant sensor (see Radiator Fan); revisit only if condenser airflow proves insufficient.

R2.8 ECM A/C Integration

The CM2220 ECM used by the R2.8 has no A/C request input pin, so PMU-to-ECM A/C signaling is not applicable for this build. A/C clutch engagement may cause a slight idle dip but not enough to require compensation.

Outstanding Items

TBD tracker unavailable

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  • PMU Outputs - OUT5 and OUT17 configuration
  • PMU Inputs - In 9 A/C request
  • iBooster - Vacuum-independent braking (no engine vacuum used anywhere in the build)
  • Radiator Fan - Fan control (independent of A/C trinary fan signal)

  1. Owner confirmation, 2026-06-11 — custom kit ordered from restomodair.com. Model/configuration per order confirmation; update this page when the unit arrives. ↩

  2. Restomod Air product line is "fully electronic aftermarket a/c system kits" with electronic control heads (no vacuum actuation). restomodair.com, accessed 2026-06-11. ↩

  3. Restomod Air trinary switch: 30 psi low-pressure cutout, 406 psi high-pressure cutout, electric fan signal at 254 psi. restomodair.com/support/trinary-switch/, accessed 2026-06-11. ↩