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Type :
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starter solenoid switch
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Specification :
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24V
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Pulley :
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Brand :
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NUOJIN
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Number :
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4HF1 8970656020
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Quality :
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NEW
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Delivery time :
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7--10DAY
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Installation Method of 24V Starter Solenoid Switch (Magnetic Switch) for ISUZU NKR66/NPR72G, NISSAN Cabstar/Atlas/Condor, BOGDAN/ATAMAN Series (Original Factory Standard Procedure)
Core Premises
Applicable Models: 24V starter motors matching engines such as 4BE1/4HE1/4HG1/4HK1/FE6, covering ISUZU NKR66 (06.1987-), NPR72G, NISSAN Cabstar (04.1985-), YE03/YGF03 (01.1980-), Atlas/Condor SGH40/SH40/SQH40, ATAMAN A-092 (01.2012-), BOGDAN A-091 (01.2000-12.2003)/A-092 (01.2003-12.2012).
Safety First: Disconnect the negative terminal of the battery first (for 24V systems, disconnect the main negative terminal first, then the negative terminals of series-connected batteries) to prevent short circuits that could burn wires or the solenoid switch.
Spare Part Requirements: Use original or equivalent-specification 24V solenoid switches (equipped with shift fork hooks, return springs, fixing bolts, terminal nuts, and waterproof rubber rings). Never mix with 12V switches.
Tools: Socket set (10/12/14mm), torque wrench, needle-nose pliers, flathead/Phillips screwdrivers, multimeter, high-temperature lithium-based grease, cleaning cloths.
1. Pre-installation Preparation (Key Inspection to Avoid Rework)
Cleaning: Thoroughly clean the starter housing, solenoid switch mounting surface, shift fork shaft, and plunger hole to remove oil, iron filings, and rust. Check the flatness of the mounting surface for no deformation or cracks.
Part Inspection
Solenoid Switch: Ensure the plunger moves without jamming; check the coil for open/short circuits (measure terminal resistance with a multimeter: 24V switches should be approximately 3–5Ω. Infinite resistance indicates an open circuit; resistance close to 0 indicates a short circuit). Verify that the hook is not deformed and the return spring has sufficient elasticity.
Shift Fork: Check for no cracks or deformation; ensure the pivot pin hole is not worn. Confirm the shift fork pivot pin and circlip are intact.
Overrunning Clutch: Ensure the pinion gear has no chipped teeth or slipping (locks counterclockwise, rotates clockwise freely) and the splines are not worn.
Terminals: Check for no burning or damage; ensure threads are intact and insulation washers are not broken.
Pre-lubrication: Apply a thin layer of high-temperature lithium-based grease to the shift fork shaft, plunger guide sleeve, and overrunning clutch splines. Do not apply grease to the solenoid switch coil or terminals.
2. Installation of Solenoid Switch Body (Inside the Starter Assembly)
Connecting the Shift Fork and Plunger Hook
Install the shift fork into the starter housing, insert the pivot pin, and secure it with the circlip (ensure the shift fork swings freely without jamming).
Align the hook on the end of the solenoid switch plunger with the groove at the upper end of the shift fork. First fit the return spring over the plunger, then push the plunger into the switch housing to fully engage the hook with the shift fork (gently push the plunger to confirm the shift fork swings synchronously).
Note: For models with a plunger pushrod, align the pushrod with the center of the shift fork to prevent bending.
Securing the Solenoid Switch
Align the solenoid switch assembly with the mounting holes on the starter housing. Use 2 (or 4) fixing bolts (original specification: M6/M8, torque: 8–12N·m). Screw in 2–3 turns by hand first, then tighten crosswise and evenly. Never tighten a single bolt first, as this may deform the housing and jam the plunger.
Inspection: Confirm the plunger extends and retracts smoothly, and the shift fork swings without interference. Ensure the switch housing fits tightly against the starter housing with no gaps.
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Precautions for Installation of 24V Starter Solenoid Switch for ISUZU/NISSAN/BOGDAN/ATAMAN Models
This set of precautions applies to the 24V starter solenoid switches matching engines including 4BE1/4HE1/4HG1/4HK1/FE6, covering models such as ISUZU NKR66/NPR72G, NISSAN Cabstar/Atlas/Condor, BOGDAN A-091/A-092, and ATAMAN A-092.
I. Safety Precautions Before Installation
1. Thorough Power-off Operation
Most 24V systems adopt dual-battery series connection. First disconnect the main negative cable, then disconnect the negative terminals of the individual batteries to prevent wire harness short circuits during installation, which may cause solenoid switch coil burnout, wire harness ignition, or electric shock to operators.
Wait 3–5 minutes after power-off to discharge residual electricity in the starter and circuit, so as to avoid accidental contact triggering the pull-in action.
2. Consistency Check of Spare Parts
Only use original or equivalent-specification 24V solenoid switches. Never mix with 12V solenoid switches—applying 24V voltage to a 12V switch will cause instantaneous overheating and burnout of the coil.
Check the mounting hole spacing, plunger stroke, and hook specifications of the solenoid switch to ensure they are fully matched with the original starter shift fork. Otherwise, faults such as improper meshing and jamming will occur.
3. Preparation of Environment and Tools
The installation site shall be clean and free of oil stains to prevent impurities from entering the plunger guide sleeve or meshing mechanism.
Tools shall be insulated (especially wrenches and screwdrivers) to avoid short circuits caused by metal tools touching both the B+ terminal and the ground terminal at the same time.
Prepare a multimeter and a torque wrench. Never tighten bolts by hand feel.
II. Operational Precautions During Installation
1. Key Points of Mechanical Assembly
When connecting the shift fork to the plunger hook, ensure that the return spring is correctly sleeved on the plunger, and both ends of the spring are clamped into the switch housing and the plunger limit groove respectively. Otherwise, the pinion gear cannot reset, resulting in dragging noise after starting.
The fixing bolts of the solenoid switch shall be tightened crosswise and evenly in strict accordance with the torque standard of 8–12N·m. Loose bolts will cause switch vibration and displacement, while over-tightening will lead to housing deformation and plunger jamming.
The circlip of the shift fork pivot pin must be fully clamped into the clamping groove to prevent the pivot pin from falling off and causing shift fork failure. Before assembly, apply high-temperature lithium-based grease to the shift fork shaft and plunger guide sleeve. Never apply grease to electrical components such as coils and terminals.
2. Standard Requirements for Electrical Wiring
The main power terminal (B+) shall be connected to a 24V positive cable with a cross-sectional area of ≥35mm². Install flat washers and spring washers, and tighten them according to the torque of 12–15N·m. Do not expose the wire core, otherwise heating and ablation will occur under high current.
The control terminal (S) shall be connected to the ignition switch starter control wire, with the torque controlled at 4–6N·m to avoid poor contact caused by loose wiring, which may lead to the fault of "intermittent pull-in".
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References:
I. Original Vehicle Maintenance Manuals (Core Sources, Corresponding to Specific Models)
ISUZU Original Maintenance Manual
Applicable Models: NKR66 (06.1987-), NPR72G, engines 4BE1/4HK1/4HG1
Chapter:
Electrical System →
Starting System →
Starter Assembly Disassembly, Assembly and Solenoid Switch ReplacementVersion: 1987/2012 editions for NKR/NPR series (corresponding to 4BE1/4HK1 engines). Electronic versions are available for download on the
Isuzu Global Service Network.
Key Content: Installation torque of 24V solenoid switch, wiring specifications, plunger stroke and shift fork meshing standards, static/dynamic test procedures.
NISSAN Original Maintenance Manual
Applicable Models: Cabstar (04.1985-), YE03/YGF03 (01.1980-), Atlas/Condor SGH40/SH40/SQH40, engine FE6
Chapter:
Electrical System →
Starting System →
Starter Motor & Solenoid ReplacementVersion: 1985 edition for Cabstar, 1980 edition for Atlas/Condor. Accessible via the
Nissan Service Information (NSI) system.
Key Content: Wiring sequence of 24V dual batteries, grounding surface treatment, waterproof sealing specifications, time limits for starting tests.
BOGDAN/ATAMAN Original Technical Bulletins
Applicable Models: A-091 (01.2000-12.2003), A-092 (01.2003-12.2012/01.2012-), 4.6D engines 4HE1/4HF1/4HG1/4HK1
Sources:
BOGDAN Service Manual (Ukrainian BOGDAN original factory),
ATAMAN Technical Bulletin 2012-01 (ATAMAN matching specifications for ISUZU engine starting systems)
Key Content: Selection standards for solenoid switches matching imported ISUZU engines, installation torque tolerances, fault diagnosis thresholds.
II. Industry National Standards & International Standards (General Technical Basis)
GB/T 19062-2018 Technical Requirements for Automobile Starters
Issued by: State Administration for Market Regulation, Standardization Administration of the People's Republic of China
Core Clauses: Performance indicators of 24V starter solenoid switches, installation dimension tolerances, terminal insulation requirements, static pull-in/release test methods, temperature rise and durability standards.
Applicability: All domestic/imported commercial vehicle 24V starters; it is a mandatory reference standard for domestic maintenance and production.
SAE J1763 Starter Motor Solenoids - Performance and Test Methods
Issued by: SAE International (Society of Automotive Engineers)
Core Clauses: Solenoid switch coil resistance range (24V: 3–5Ω), plunger stroke, return spring elasticity, contact ablation threshold, installation torque specifications.
Applicability: Design and installation standards for 24V solenoid switches of international supporting suppliers (BOSCH/DENSO/VALEO).
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