Forklift won’t start – Here’s how to diagnose the problem

Your forklift won’t start. The shipment has arrived at your dock with your raw materials for the hot job you need to get started on. You jump on the forklift to unload and turn the key. Nothing happens, no starter growling it’s just dead. What do you do? The repair man says he can’t make it out until tomorrow. You need to get this done so here is where to start.

Basic troubleshooting for a no start condition

There are some easy steps that you can take to simplify the process. Your headlights can tell you a lot about what is going on. The very first thing to do is check to see if the lights work. If they turn on, are they bright? Do they dim when you blow the horn? This quick test

Forklift won’t start test tool

can tell you a lot about your system. If the lights did not light at all you may have a blown main power fuse, corroded battery connections. Loose or broken ground connection. Don’t forget to check the connection at the starter and or starter solenoid.  If the lights come on but dim when horn is blown or start switch is turned your problem is likely a dead battery or bad connection.

If you have a VOM (volts-ohm-meter) you can check the voltage. A fully charged battery will read approximately 13.2 volts. If the voltage drops at the battery terminals under  load this indicates that

forklift VOM meter

the battery is probably the source of your problem and needs further testing.  Fully charge the battery and retest. If the battery does not take a full 13.2 v charge it is time to replace. If your battery is good and you still have a problem you can continue to diagnose by moving your  lead down the line you can determine the location of the problem by locating the point that the voltage drops off.  A simple test light can be used for this process.

If you have battery voltage at the starter solenoid but you do not hear an audible click when the start switch is activated then you may need to replace the solenoid.

A typical start circuit consists of a fuse, ignition switch, forklift brake switch, neutral switch, seat switch, and starter solenoid. Your system may vary. The newer the forklift the more complex they have become. Other features found on newer forklifts include but are not limited to: brake pedal switch, seat belt switch, mast height limiter switch, Dead man switch, etc.

forklift starter circuit diagram
forklift starter circuit diagram

Check all components for continuity and adjustment. Often a visual check of these areas will reveal the problem.

This tutorial is not intended as a comprehensive repair guide. Hopefully it will help you find the most common causes of a no start condition involving the starter circuit. It would take a small book to go over every potential cause for the starter to not engage. If you cannot find the problem using this guide then I suggest that it may be time to call in the professional.

Consider yourself fortunate if you are working on an older forklift. These are generally much simpler to diagnose and repair. The circuits in these older trucks are generally wired in series. When the non-functioning part is found a simple wiring repair, adjustment or component replacement is all that is needed to get your unit up and running.

Look for future articles discussing what to do if your engine turns over but does not start.  Learn more about our toyota forklift starter and other  forklift starters here.


Post by Intella Liftparts