The 803689000 Relay is a genuine OEM electromechanical relay manufactured by XCMG for motor graders and heavy construction machinery. This ISO mini relay (form factor 1) provides reliable switching for lighting circuits, starter solenoids, horn systems, and auxiliary equipment on XCMG GR series graders.
Designed to withstand extreme vibration, voltage spikes, and temperature variations, the 803689000 relay features silver-tin oxide contacts and a sealed, dust-resistant housing. It directly replaces failed or chattering relays on XCMG motor graders and compatible heavy equipment.
Each unit is rated for 30A at 24V DC (resistive) and 20A at 24V DC (inductive), with a standard 5-pin changeover configuration (SPDT). The built-in resistor across the coil suppresses back-EMF, protecting sensitive electronics from voltage spikes.
| Parameter | Specification |
|---|---|
| OEM Number | 803689000 |
| Brand | XCMG (Genuine Original Equipment) |
| Product Type | ISO Mini Relay – SPDT (Form C, changeover) |
| Coil Voltage | 24V DC (operating range 18V – 32V) |
| Coil Resistance | 650 Ω ±10% (at 23°C) |
| Coil Power Consumption | 0.9 W (nominal) |
| Contact Arrangement | 1 Form C (SPDT): terminal 30 common, 87a NC, 87 NO |
| Contact Material | Silver-tin oxide (AgSnO₂), high welding resistance |
| Resistive Load Rating | 30A @ 24V DC |
| Inductive Load Rating | 20A @ 24V DC (L/R = 40ms) |
| Maximum Inrush Current | 100A for 10ms |
| Switching Voltage Max | 30V DC / 300V AC |
| Pick-Up Voltage | ≤ 14.4V DC |
| Drop-Out Voltage | ≥ 2.4V DC |
| Operate Time (typical) | ≤ 10 ms |
| Release Time (typical) | ≤ 5 ms |
| Mechanical Life | 10,000,000 operations (no load) |
| Electrical Life | 200,000 operations at rated resistive load |
| Terminal Type | 6.3 mm quick-connect (ISO 7588 / micro relay footprint) |
| Mounting Type | Plug-in (relay socket required, order separately) |
| Ingress Protection | IP54 (dust-protected, splash-resistant housing) |
| Operating Temperature | -40°C to +85°C |
| Storage Temperature | -40°C to +100°C |
| Housing Material | PBT (UL94 V-0 flame retardant) |
| Coil Suppression | Built-in resistor (1kΩ) for back-EMF protection |
| Reverse Polarity Protection | No (install correctly; incorrect wiring will damage coil) |
| Compatible Models | XCMG GR135, GR165, GR180, GR215, GR260, GR300, GR350 motor graders; also XCMG loaders, rollers, excavators |
| Superseded Part Numbers | 803688501, 803688712, 803688890, 803688956 |
| Certifications | CE, RoHS, ISO 9001:2015, IATF 16949 |
The XCMG 803689000 Relay is a critical component for controlling high-current loads with low-power switches. It uses an electromagnetic coil to pull in a set of contacts, allowing a small current from a switch or ECU to turn on or off devices such as work lights, heater blowers, starter solenoids, and hydraulic valve solenoids.
The relay’s SPDT (single pole double throw) configuration provides both normally open (NO) and normally closed (NC) contacts. Terminal 87 is NO (off when coil is de-energized, on when energized), terminal 87a is NC (on when de-energized, off when energized). This versatility allows it to be used for both high-side switching and changeover applications.
Unlike cheap automotive relays, the 803689000 is built with silver-tin oxide contacts that resist welding and pitting, even when switching inductive loads like motors and solenoids. The contact gap is optimized for 24V systems, ensuring arc extinction without excessive contact erosion.
The 803689000 relay is a direct plug-in replacement for the original equipment on XCMG GR series motor graders. It fits standard ISO mini relay sockets (commonly used in fuse/relay boxes). The pin configuration is industry-standard: terminal 85 and 86 for coil, 30 common, 87a NC, 87 NO.
Installation is simple: locate the faulty relay (often identified by visible melting, chattering, or non-functioning circuit). Pull it straight out of the socket, and push the new 803689000 in until fully seated. No tools required. Always verify that the replacement relay has the same pinout (a common cause of incorrect replacement is using 5-pin vs 4-pin relays).
Common failure symptoms: the controlled device (e.g., lights, horn) does not operate, operates intermittently, or stays on all the time. A clicking sound without function may indicate burned contacts. Replace immediately to avoid damage to the switch or ECU.
XCMG tests each batch of 803689000 relays to ensure reliability in extreme conditions. Tests include 500 hours of salt spray (ASTM B117) with no visible corrosion, 100 thermal shock cycles from -40°C to +85°C, and 20g vibration for 24 hours across 10-2000Hz. The relay also passes load dump pulses per ISO 7637-2 and reverse battery protection tests (though polarity must be observed).
The PBT housing is UL94 V-0 flame retardant and resists cracking from UV exposure. The terminals are tin-plated brass with a retention force of >50 N. The coil wire is encapsulated in epoxy, preventing moisture-induced corrosion. The IP54 rating ensures protection against dust and water splashes, suitable for engine compartments and cab fuse panels.
Electrical life is verified at 200,000 cycles at 30A resistive load, with contact resistance remaining below 50 mΩ throughout. Mechanical life exceeds 10 million cycles, making this relay suitable for high-frequency applications such as flashing lights or pulse-width modulated controls.
Aftermarket relays often use copper contacts (instead of silver-tin oxide) that arc-weld under load, causing stuck contacts and continuous operation. The genuine XCMG relay uses high-quality contact materials rated for 24V heavy equipment. Many generic relays are designed for 12V cars and fail prematurely when used at 24V due to insufficient contact gap and arc suppression.
Counterfeit relays may omit the back-EMF suppression resistor, causing voltage spikes that damage ECU outputs or cause false triggering. The 803689000 includes a 1kΩ resistor across the coil, protecting sensitive electronics. Also, genuine relays have laser-etched XCMG logo and part number for traceability.
XCMG provides a 12-month unlimited-hour warranty against manufacturing defects. Using genuine relays ensures compliance with original equipment specifications and prevents costly electrical system damage.
To test the 803689000 relay, remove it from the socket and use a multimeter. Measure resistance between terminals 85 and 86: should be 650Ω ±10%. If open or short, the coil is faulty. Next, check continuity between 30 and 87a (NC contact): should be <0.5Ω. Between 30 and 87 (NO): should be open (infinite).
Apply 24V DC to terminals 85 (+) and 86 (-). You should hear a distinct click. Now measure between 30 and 87: should be <0.5Ω. Between 30 and 87a: should be open. If the relay clicks but contacts do not change, the contacts are welded or damaged. Replace the relay.
If the relay tests good but the circuit still does not work, check the relay socket for corrosion, loose terminals, or melted plastic. Also verify the fuse and the load device (e.g., light bulb, motor). For intermittent failures, try swapping with a known good relay.
The 803689000 Relay is stocked in XCMG’s regional warehouses in North America (Houston), Europe (Rotterdam), Middle East (Dubai), and Asia (Shanghai). Standard air freight delivers within 3-7 business days worldwide. Expedited shipping (1-2 days) is available for urgent repairs.
Bulk orders (20+ pieces) receive volume discounts and can be shipped via sea freight. Each relay is individually bagged with desiccant and anti-static protection. For large fleets, consignment stock programs ensure immediate availability and reduced downtime.
Don’t let a failed relay disable critical equipment. Order the genuine XCMG 803689000 Relay today and ensure your motor grader’s electrical systems operate reliably. Genuine quality, perfect fit, and long service life – designed for the toughest jobsites.
The 803689000 Relay is a fundamental building block of your motor grader’s electrical system. From headlights and work lights to starter circuits and hydraulic solenoids, this relay ensures reliable switching under the harshest conditions. Keep spare relays in your maintenance kit for rapid field repairs.
Upgrade or replace your worn relays today. The XCMG 803689000 offers superior contact material, robust coil isolation, and extreme environmental resistance – everything you expect from original equipment. Order now and keep your grader productive and safe.
