Dexter Washer Error Code F18: Drive Ground
F18 means the drive detected current leaking to ground. Do not reset the power until a technician reads the light code on the drive. Wiring to the drive and motor, and the ground connections, need checking.
High: a ground leak is a shock hazard as well as a stop.
What does Dexter error code F18 mean?
A drive expects all the current that leaves on the motor leads to come back on the same leads. If some of it finds its way to ground, through a damaged wire or a poor ground connection, the drive trips and the control shows F18. The Common Washer guide labels this alarm DRIVE GFI. The manual says to check the drive light code before power is turned off, since it is lost on power-down. Then check the wiring to the drive and the motor, the ground wiring of the drive, the motor and the incoming connection, and look for damaged motor wires. The causes it lists are a poor ground and damaged motor wires. A ground problem is a safety matter as well as an alarm, because a leaking current can energize the washer frame. So F18 deserves a careful check rather than repeated resets.
Affected models and control systems
Dexter T-450 SWD Express stack washer-dryers, serial 481983 and up. The same F10 to F21 table appears in the WCAD-Series vended washers manual (8533-073-001, 11/11). Older Dexter washers number their drive codes differently.
Code numbers and their meaning can change between control generations. We match the full model and control before acting on a code.
What you may notice
- F18 on the display
- Cycle stops at motor start
- Tingling felt when touching the washer frame (stop and call at once)
Possible causes
Listed in Dexter's documentation
- Poor ground
- Damaged motor wires
Other likely causes — what usually sits behind error code F18 on this control. A technician confirms which one it is before any part is replaced.
- Motor lead rubbed through on a sharp edge
- Moisture in the motor terminal box
- Loose ground lug at the incoming feed
Safe checks before calling for service
- Do not touch the washer frame if you feel any tingle. Switch it off at the disconnect.
- If it is safe, leave the drive lights as they are so a technician can read them.
- Check for water on or around the washer.
- Call for service and tell the technician about any shock or leak.
How a technician diagnoses error code F18
- Read the drive light code before power off.
- Inspect the wiring to the drive and the motor.
- Check the ground wiring at the drive, motor and incoming connection.
- Test the motor leads for insulation damage with a meter.
- Replace damaged leads or repair the ground.
- A ground problem can make the washer frame live and cause shock.
- Insulation tests need the correct meter and a locked-out supply.
- Wiring repair at the drive is electrician-level work.
How error code F18 differs from similar codes
F18 is the ground alarm. F14 is over-current and F17 is overload.
Technical reference
- Maker documentation
- Dexter owner support
- Edition
- Part # 8533-070-001 (12/13), starting serial number 481983
- Models / control
- Dexter C-Series and T-series coin washers with VFD (T-300 to T-1450)
- Section
- Troubleshooting Washer Fault Errors (F-Codes), p.6-10
- Checked
- October 2026
We use the maker's document to read the code and do not reproduce it. Always confirm the complete model and control before applying these steps.
Related Dexter washer error codes
Is F18 dangerous?
It can be. A ground leakage can energize metal parts, so treat it as a safety alarm.
Can I reset and keep going?
No. Have the grounds and wiring checked first.
What is DRIVE GFI?
The Common Washer guide's label for the same alarm.
Need help with Dexter error code F18?
A technician confirms the cause on site and gives you the price in writing before any work starts.