Motor goes one way but won't go the other (e.g. down but not up)
A reversing drive works in one direction only. One command (say, down) runs fine; the other (up) does nothing, or just hums/trips. Common on hoists, doors, and conveyors.
Safety first
Reversing gear often drives hoists, doors, and lifts — anything that moves can crush. Confirm the load is mechanically secured and the area clear before testing direction commands.
Isolate, lock out / tag out, and prove dead before working unless a live test is specifically required, authorised, and carried out under proper supervision. Always follow local regulations, your site procedures, and the equipment manufacturer's documentation.
Full detail — causes, the why, and common mistakes.
Likely causes
Ranked from most to least likely.
- 1
Failed direction contactor (the 'up' one)
Most likelyEach direction usually has its own contactor. If the up contactor's coil or contacts have failed, that direction is dead while the other still works.
- 2
Tripped/triggered direction limit or interlock
#2An end-of-travel limit, slack-rope switch, or safety interlock for that direction is opening the circuit, so the command can't get through.
- 3
Broken control wiring or button for one direction
#3A faulty 'up' pushbutton, broken pendant wire, or open seal-in contact only affects that one direction's control path.
- 4
Mechanical end-stop or jammed load in that direction
#4The load is already against a physical end-stop or jammed, so it can't travel further that way even though the electrics are fine.
- 5
Phase/contact issue causing a trip only one way
Least likelyA weak contact on one direction contactor can cause single-phasing that trips or stalls only when that contactor is used.
Reports are saved on this device to reflect what you actually find.
Testing sequence
Work through one test at a time. Expected reading and what each result means.
Operate the failing direction and listen/look: does the direction contactor try to pull in at all?
The up contactor energises (clunk) when you press up.
The contactor is being commanded — focus on the contactor contacts, motor connection, or a trip.
The contactor isn't being told to come in — the fault is in that direction's control path (button, wiring, limit, interlock).
View all expected readings at once
Fault-finding flowchart
The same logic as a decision tree.
- 1start
Runs one way, not the other
→ step 2 - 2decision
Does the failing-direction contactor pull in when commanded?
Yes→ step 3No→ step 4 - 3decision
Are the contactor's main contacts good and is there travel left?
Yes→ step 5No→ step 6 - 4decision
Is that direction's control path (limit/interlock/button) complete?
Yes→ step 7No→ step 8 - 5result
Check motor wiring and for single-phasing on that direction's path.
- 6result
Burnt contacts or at end-of-travel. Replace contacts / confirm position.
- 7result
Path complete but coil won't pull in — see contactor coil fault-finding.
- 8result
Open limit, interlock, or button is blocking the command. Repair that path.
Common mistakes apprentices make
- Assuming the motor is faulty when only one direction's contactor or limit has failed — the other direction proves the motor turns.
- Forgetting the mechanical interlock between the two contactors and condemning a contactor that's actually being held off.
- Not checking the end-of-travel limit for the failing direction.
- Swapping the motor before proving the up command even reaches the contactor.
When to stop & escalate
On hoists, lifts, and doors, any safety interlock or end-of-travel limit found operating should be confirmed against the machine's safety design before being adjusted or bypassed. If the load is jammed mechanically, hand it to the mechanical team.
If you're past your competence, authorisation, or the safe limits of the job — stop and hand it on. There's no fault worth getting hurt over.
Related faults
Contactor has voltage at the coil but won't pull in
You measure the rated control voltage (e.g. 24V) across the coil terminals, but the contactor refuses to energise — no clunk, no pull-in, contacts stay open.
Limit switch or proximity sensor not being detected
A limit switch or proximity/photo sensor isn't registering — the machine doesn't stop at position, the input never makes, or the sensor LED looks wrong for the target's position.
Motor overload keeps tripping
The thermal/electronic overload trips repeatedly, either on start or after the motor has run for a while. Resetting only buys you a short run before it trips again.
Learn the theory
How the gear and circuits behind this fault actually work.