If you work in construction, facility maintenance, or industrial installation, you know how critical a properly functioning articulated boom lift is to getting jobs done safely and on time. As a supplier of these machines, I’ve spent years walking operators through troubleshooting common issues, and I can tell you that most breakdowns aren’t fatal—they’re just small, fixable problems that people often overlook. Today, I’m going to break down a step-by-step troubleshooting process that I use with every customer who reaches out with a boom lift issue, all based on real-world cases we’ve encountered in our fleet over the years. Articulated Boom Lift
First, let’s start with the basics you should always check before diving into more complex systems. I see so many operators waste time tearing apart hydraulic lines or checking electrical sensors when the problem is as simple as a dead battery, a loose emergency stop button, or a blocked access gate. Every time a lift doesn’t start or won’t move, I tell our team to run what we call the “Pre-Trip Quick Check” first. Start at the base unit: make sure the battery terminals are clean and tight—corrosion here is one of the top causes of no-start issues. Next, confirm the emergency stop (E-stop) button isn’t engaged. It sounds obvious, but after a rental turn-around, a maintenance worker might bump the E-stop and forget to release it, and that’s enough to keep the lift from powering up. Then, check the platform access gate: most modern booms have a safety interlock that cuts power if the gate is open, so even a partially closed gate can prevent you from extending the boom. If the lift runs on fuel (not just battery), verify the fuel level isn’t below the minimum mark and that the fuel shut-off valve is open. These steps take five minutes, and in 60% of the issues we resolve, this is all you need to fix the problem.
Now, let’s move to the most common operational issues: the boom won’t articulate, lift, or extend horizontally. This is where hydraulic systems come into play, and I want to emphasize that safety is non-negotiable here—always engage the lift’s safety locks before working on hydraulic components. If your boom won’t lift, first check the hydraulic fluid level. Low fluid is another super common issue; fluid can leak slowly over time from seals or hoses, and if it drops below the reservoir’s “add” line, the hydraulic pump can’t build enough pressure to move the boom. To check this, park the lift on level ground, lower the boom fully, and let the engine run for a minute before checking the reservoir—this allows the fluid to settle, giving you an accurate reading. If the level is low, add the manufacturer-recommended fluid (using the wrong viscosity can cause issues too—we always tell customers to use what’s listed in the operator’s manual, not a random hydraulic fluid from the shop).
If the fluid level is good, check for hydraulic leaks. Small leaks might look insignificant, but they can reduce pressure enough to stop the boom from moving. Look at all the hoses, connections, and seals near the base of the boom, the articulation joints, and the lift cylinders. A slow leak might leave a small damp spot, while a major leak will have visible drips. If you find a leak, never attempt to plug it with tape or a makeshift fix—hydraulic fluid is under extremely high pressure, and a small leak can spray fluid with enough force to penetrate skin, which is a serious injury risk. Instead, shut off the lift, relieve hydraulic pressure by running the boom through a full cycle, and either schedule a replacement hose or contact a technician to repair the seal.
For articulation issues specifically—where the boom won’t bend at the joints or won’t rotate at the base—another common culprit is a faulty directional control valve. This valve is what directs hydraulic fluid to the different cylinders that control each joint. If the valve is clogged with debris (dust, dirt, or old fluid residue from a filter change that went wrong), it won’t send fluid to the right joint. To check this, we recommend testing each function one at a time: try articulating the main boom first, then the secondary boom, then the base rotation. If only one function is failing, it’s likely the control valve for that joint. We also suggest checking the hydraulic filter—if the filter is clogged, it can restrict fluid flow to all functions, so replacing the filter might solve the issue before you even touch the valve.
Next, let’s talk about electrical issues, which are getting more common in newer articulated boom lifts that have electric controls for articulation and platform functions. A lot of operators assume electrical issues are too complex, but there are a few simple checks you can do first. If the controls in the platform aren’t working (but the base controls are fine), the first thing to check is the communication cable between the base unit and the platform. This cable runs along the boom, and it can get pinched, frayed, or damaged over time from bending as the boom articulates. Inspect the entire length of the cable for visible cuts or kinks, and check the connectors at both ends—make sure they’re locked in and not corroded. Corroded connectors are a big one for intermittent issues: one minute the controls work, the next they don’t, because the corrosion breaks the electrical connection. You can clean connectors with a soft brush and electrical contact cleaner, but if the pins are bent or broken, you’ll need to replace the connector.
Another electrical issue we see is faulty limit switches. Every articulated boom has limit switches that prevent the boom from extending too far or articulating beyond its safe range. These switches can get bumped out of alignment, or their contacts can get dirty, which makes them trigger incorrectly. For example, if the main boom won’t extend all the way, even when you push the control, the end-of-stroke limit switch might be triggering prematurely. To test a limit switch, locate it near the joint or cylinder it controls, and gently adjust its position a quarter-inch away from the trigger point. If the function works after that, you’ve found the problem. If not, you can use a multimeter to check if the switch is getting power when it’s activated—if it isn’t, the switch might be bad and need replacement.
Intermittent issues are the trickiest to troubleshoot, because the problem only shows up sometimes. I’ve had customers tell me their boom works fine one day and won’t move the next, and nine times out of ten, it’s a loose wire or a worn sensor. I always suggest tracing the wiring harness for any loose connections, especially around moving parts like the base rotation or boom joints, where vibration can shake wires loose. Another common intermittent issue is a worn ground fault interrupter (GFI) in the platform power outlet, if your lift has one. The GFI is designed to cut power if there’s a ground fault, but over time, it can trip randomly if it’s old or worn. Test the GFI by resetting it—if it trips again right away, there might be a fault in the outlet, but if it stays reset, the GFI itself is failing and needs to be replaced.
No matter what issue you’re having, there are a few safety rules I can’t stress enough during troubleshooting. First, always turn off the lift’s engine and engage all safety locks before working on any mechanical or electrical components. Never work on the boom while it’s elevated unless you’re trained and have proper fall protection, and never bypass safety interlocks—they’re there to prevent accidents. If you’re not confident in your ability to troubleshoot a problem, don’t hesitate to reach out for help. Our team is here to walk you through step-by-step, or we can send a technician on-site if the issue is more complex.
After you’ve troubleshooted and fixed the issue, it’s a good practice to run a full function test: extend the boom fully, articulate all joints, test the platform controls, and make sure the E-stop works correctly. This will confirm you’ve resolved the problem and catch any other small issues before they cause a breakdown on the job site.
At the end of the day, an articulated boom lift is a heavy-duty machine, but most of its issues are preventable with regular maintenance and basic troubleshooting. If you’re dealing with a persistent issue that you can’t resolve, or if you’re in the market for a reliable articulated boom lift for your operations, don’t hesitate to get in touch to discuss your needs. Our team has years of experience working with all types of booms, and we can help you find the right machine, provide maintenance support, or assist with any troubleshooting questions you have.
Scissor Lift References:
- Occupational Safety and Health Administration. (2022). Powered Platforms for Construction Use: Articulating Boom Lifts. OSHA 3153.
- Association of Equipment Manufacturers. (2021). Articulated Boom Lift Operational and Maintenance Best Practices. AEM Technical Report 10-21.
- Caterpillar Inc. (2020). Hydraulic System Troubleshooting Guide for Heavy Construction Equipment. CAT Technical Publication HYD-TRB-20.
- International Organization for Standardization. (2019). Safety Requirements for Aerial Work Platforms. ISO 18878:2019.
- JLG Industries, Inc. (2021). Articulated Boom Lift Electrical and Control System Troubleshooting Manual. JLG Pub-10017654-R4.
Shandong Zhongke Huali Machinery Co., Ltd.
As one of the most professional articulated boom lift manufacturers and suppliers in China, we also support customized service. We warmly welcome you to wholesale discount articulated boom lift in stock here from our factory. For price consultation, contact us.
Address: No. 2 Qubai Road, Qudi Street, Jiyang District, Jinan City, Shandong Province
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