Description

Grove CM20 Installation Manual – Factory Specs, Not Aftermarket Guessing

I’ve seen more botched LMI installs than I care to count. Guys grab a generic wiring diagram off some forum, guess at the torque on the pressure transducer fittings, and then wonder why the system throws errors on the first lift. That’s what happens when you skip the Grove CM20 Installation Manual. This 78-page factory document from Grove (a Grove Worldwide Company) isn’t someone’s aftermarket interpretation – it’s the exact binder that leaves Shady Grove, Pennsylvania. If you’re installing a CM20 LMI system on a crane or retrofitting an existing machine, this is your only shot at getting the pressure transducer connections, DS350 central unit wiring, and A2B flags right the first time.

CM20 LMI System – What the Manual Actually Covers

The Table of Contents runs twelve major sections. Everything from Superstructure Installation to Decal Installation (English, Spanish, French). You get the full Bill of Material for every subassembly: CPU assembly, cable reel, junction boxes, console assembly, light bar, inclination sensor, third-wrap limits on main and auxiliary hoists, crawler extension, and every boom extension – fixed swingaway, tele-offset, auxiliary nose. Page 4 shows the superstructure layout: central unit DS350, cable with 14-conductor plug, pressure transducers (piston and rod), hoist pressure switches, crane interface, console, datalogger, and fuse placement (2A and 10A).

Pressure Transducer Connection – Why the Seal Matters

Then you see the BOM: part number 9-333-101469 for two pressure transducers and 9-333-101472 for cutting seals. Those seals are not optional. I’ve watched a tech install a transducer without the seal, get a slow hydraulic leak, and then blame the transducer. The manual specifies the cutting seal because it’s designed to handle 5,000 psi peaks. Page 2 of the superstructure section has the torque callout for the strain reliefs: tighten securely but do not over-tighten. No generic torque chart – that note is specific to the CM20 harness.

Wiring Schematics – DS350 CPU and Central Unit

Central Unit DS350 Wiring Schematic is its own section. The manual includes the full pinout for the 14-pin female plug, the cable assembly part number 9-333-102706, and the routing diagram. You also get the Main Boom Nose Wiring Schematic, the Console Connection Electrical Wiring, and the Proximity Switch Wiring for tracks extended. Each schematic is accompanied by a Bill of Material listing every connector, fuse, and wire gauge. No aftermarket manual reproduces this level of detail because the reproduction rights belong to Grove. This is the only source for factory-correct wiring diagrams that match the OEM harness.

7 Key Assembly Steps You Can’t Skip

1. Superstructure Installation – mounts the DS350 central unit inside the toolbox. Bolts 5/16-18 NC x 1 inch, grade 5, with lockwashers and hex nuts (part numbers listed).
2. LMI Mounting Hardware – includes the bracket kit and all fasteners.
3. A2B System Installation – cable reel, junction box, retainer flag assembly on the boom nose.
4. LMI Cabin Installation – console and console connection wiring.
5. Light Bar Installation – wiring to the cab indicator.
6. Inclination Sensor Installation – wiring and mounting.
7. Third-Wrap Limit Installation (main and auxiliary hoists) – includes the MWD 100 control unit assembly.

Each step has a bill of material with Grove part numbers. If a bolt is missing, you order that exact number – not an SAE-grade 2 substitute. The manual even notes to install dust covers when plugs are disconnected. That’s the kind of detail that keeps moisture out of the DS350 connector on a rainy job site.

Who Should Use This Manual – Audience and Real-World Use Case

If you own a crane with the CM20 LMI (or you’re installing a used system onto a machine that didn’t come with it), this manual is your workbench necessity. I’m a professional tech, but I’d tell a DIY owner-operator the same thing: don’t touch the wiring or the transducer fittings without the factory procedure. The system has a 2-amp fuse on the cable reel circuit and a 10-amp for the datalogger. The manual tells you exactly where each fuse goes – not a generic “install fuse” line. One wrong connection can fry the DS350 CPU assembly. That’s a thousand-dollar mistake you avoid by having the wiring schematic open on page 4.

Source Validity – OEM vs. Aftermarket Documentation

I’ve got a stack of aftermarket “crane installation guides” on my shelf. They’re useless for an LMI system because they don’t include the A2B retainer flag assembly or the specific inclination sensor wiring for the CM20. This manual is the original Grove publication, printed June 1996. Every page has the Grove logo and part number 9-333-102682. Compare that to a photocopy that lost the contrast on the wiring diagram – you try tracing a 14-conductor cable through a blur. Not happening. The manual we sell is the exact PDF of the 78-page binder. No missing pages, no third-party editing. When I need the torque for the pressure transducer mounting bolts, I turn to the page that says “Tighten strain reliefs securely, but take caution not to over tighten.” That’s the only authority I trust.

For related equipment, check the Grove Manitowoc National Crane RT9150E Technical Manual – 28 Pages if you’re working on a larger rough-terrain crane. The Grove GMK2035 1999 User Manual – Factory Operating Instructions covers operational specs for the all-terrain line. And if the CM20’s DS350 central unit programming puzzles you, the Grove DS350 Training Manual – Factory LMI Programming Guide goes into the setup menus. For general crane drive components, see the Manual Transmission and Manual Transmission references – but stay focused on the LMI installation first.

FAQ – Two Questions You’re Probably Asking

Does this manual cover the DS350 central unit programming?

No. This is strictly the installation manual – wiring, mounting, and BOM. For programming the DS350 parameters and calibration, you need the DS350 Training Manual. The installation manual does include the CPU assembly breakdown and the schematic, but not the menu trees.

Can I use this manual for a CM20 system on a non-Grove crane?

The wiring schematics and transducer connections are specific to the Grove superstructure and boom geometry. If you retrofit the CM20 onto another brand, you’ll still need this manual for the pinouts, torque values on the transducer fittings, and the A2B flag dimensions. Match the existing crane’s boom wiring to the junction box schematic in the manual. The BOM lists the exact cable lengths – you’ll have to adapt those to your crane, but all component part numbers and electrical specs apply.

Stop wasting time on generic wiring diagrams and field-modified torque values. Every crane shop I know keeps a copy of this manual in the toolbox. Access the Factory Manual now and get the install done right the first time.