Terex AC40/2, AC40/2L Wiring Diagram – 136 Pages of Factory Specs

If you’ve ever chased a short on a crane with a generic wiring schematic, you know the pain. Pinouts that don’t match, wire colors that are close but wrong, and no clue which relay feeds what. That’s exactly why I won’t touch aftermarket diagrams on a job. This Terex AC40/2, AC40/2L Wiring Diagram is the real deal – the same binder the dealer techs use. 136 pages of factory-original circuit drawings for both the AC40/2 and the AC40/2L. No reprints, no scanned-in copies with faded lines. This is the OEM file from Terex.

136 Pages of Circuit-Specific Detail

The manual opens with the electric diagram – CR108332B – running from page 3 all the way to page 123. That’s 120 pages of pure electrical layout covering every function you’d need: ENGINE START/STOP (page 5), CAN BUS CARRIER GROUND (page 8), CARRIER FUSES BEFORE IGNITION (page 9), TAIL LIGHTS / EXHAUST BRAKE (pages 15–21), EL. INJECTOR / FUEL TANK / SHUTDOWN / ENGINE (pages 23–34), STEERING / THROTLE (pages 38–45), and OUTRIGGERS BOX (pages 46–47). After the electric section come the pneumatic diagrams for both models (pages 124–125), then the hydraulic diagrams. Need the telescopic cylinder circuit? For the AC40/2L you get CR107903I for MONTAN cylinder (page 126) and CR108062H for IOTTI cylinder (page 127). The AC40/2 gets CR107972C for MONTAN (page 128). There’s also hydraulic extension diagrams, auxiliary winch diagrams, and even the severe cold option (pages 134–136) – all with cylinder-specific pinouts.

Page Index: Find the Circuit in Seconds

One thing that drives me nuts with cheap manuals is a missing index. This one has a proper page index on page 3 that lists every function by name. Need the DIMMER SWITCH? That’s page 11. WIPERS? Pages 12–14. ADHESIVE WIPER? Yes, they actually call it that. LOCKS on page 30. FRONT AND REAR INTERNALS WHEELS DIFFERENTIALS on page 35. You don’t flip through 136 pages blind – you look up the function and go. The index alone saves you ten minutes of hunting.

Does This Manual Cover the Telescopic Cylinder Circuits?

Absolutely. The hydraulic diagrams for the telescopic cylinder are broken down by manufacturer and model. For the AC40/2L you get two separate sheets: one for MONTAN cylinder (page 126) and one for IOTTI (page 127). The AC40/2 uses the MONTAN cylinder shown on page 128. If you’re working on the severe cold option, there’s even dedicated pages for both cylinder types on pages 135–136 (CR108405B for IOTTI, CR108406B for MONTAN). That level of detail is what separates an OEM wiring diagram from a parts-store hack job.

Source Validity: OEM vs Aftermarket

This is the actual manufacturer file – TEREX_AC40-2-AC40-2L_Wiring_Diagram_en-28911009803.pdf. Look at the TOC: it’s Chapter 8 of the full maintenance and operator’s manual. The page numbering, the drawing numbers (CR108332B, CR107888, etc.), the fold-out style layouts – all factory original. Aftermarket wiring diagrams for cranes often consolidate multiple circuits into one confusing schematic. Not this one. Each circuit gets its own page or set of pages. You trace a circuit from relay to load without cross-talk. That’s worth the download price alone.

3 Systems You Can Wire With This Manual

1. Engine start/stop and pre-heating – pages 5–6 show the full circuit including alternate power. 2. Outrigger controls – pages 46–48 cover the left and right outriggers boxes plus pad selection. 3. Steering and throttle – pages 36–45 break down the steering cutoffs and throttle interfaces. Every circuit has a dedicated page number. No guesswork, no misinterpretation.

FAQ – Common Questions About This Manual

Will this work for both the AC40/2 and the AC40/2L?

Yes. The manual covers both models. The hydraulic diagrams have separate pages for each variant.

Are the wiring colors and pin numbers exactly as Terex intended?

They are the factory schematics. Wire colors match the harness labels. If the diagram shows a brown wire on pin 3, that’s what you’ll find.

Does this include the pneumatic diagrams for the brake and suspension systems?

Yes, pages 124 and 125 are the pneumatic diagrams (CR107888 and CR107889) covering the AC40/2 and AC40/2L.

I need to trace the telescopic cylinder cylinder extension circuit – can I find it?

Page 130 (CR108242A) is the hydraulic extension diagram. For the exact cylinder solenoid wiring, see the telescopic cylinder diagrams on pages 126–128 and the severe cold pages 135–136.

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If you’re still relying on aftermarket wiring diagrams for your Terex crane, you’re wasting billable hours and risking a fried harness. Get the factory data straight from the source. For more on wiring best practices, see Automotive Wiring”>Automotive Wiring or Automotive Wiring”>Automotive Wiring. Download the Factory Manual and put an end to electrical guesswork.