TC reported TIMS showed obstacle detected at rear DT. Train processed as per normal. ~~~~~ 549/550 found resistance of obstacle detection loop fluctuating. Further check found wire join corroded and breaking off crimped join. Repaired join by recrimping wire and applying new heat strink over. Function check found SATIS. 3549 ODBS switch normalised and resealed N.AKUMAR/14.03.22 --------------