Hi Leon,
How are you doing ?
The direction contactors operate means that all the traction enable signals are OK. You should check the following points :
- Jack up the front wheels truck to see if the wheels are running when the direction contactors closed ?
- If only one wheel run and the other stop => you need to check the curve switch 1S1 & 1S2 in the rear wheel - near the steering cylinder.
- Check the contactor tips for worn out and bab connection, you have better change the contactor for trial since some contactor tips look still good but they have very bad connection actually.
- Check carefully the battery votage with load e.g if the battery is decreased too much during lifting ?
- It is certain that the traction burshes are still OK since you have no error but you have better check contact between the brushes and the roto of the traction motor.
- Finally, I can say you should check the speed sensor of the traction motor. This is because when the speed sensor is abnormal the controller couldn't recognize it and make the traction become crazy.
Good luck & regards
Nuna