Abstract: A unit for indicating lights (3a, 3b, 3c, 5, 6, 7) includes a cylindrical case (11). Opposite end portions (18, 19) of the case (11) are each connected with a corresponding end portion (19, 18) of a case (11) of a corresponding unit (3a, 3b, 3c, 5, 6, 7) through relative rotation of the cases. An electrical connection member (14, 140, 141, 142) extended between the opposite end portions (18, 19) of the case (11) establishes electrical connection between units (3a, 3b, 3c, 5, 6, 7) corresponding to each other. First and second ends (28, 29) of the electrical connection member (14, 140, 141, 142) are provided with first and second terminal portions (31, 31a; 32, 32a), respectively.

Abstract: A fault diagnosis circuit of the present invention includes: LED indicating units 3a, 3b, and so forth; current detecting circuits R1 and Q1 for detecting a flowing current by flowing a short-time pulse of a current through the LED indicating units 3a, 3b, and so forth based on pulses generated by a pulse generating circuit 7; comparing circuits 8 and 9 for comparing a current value detected by the current detecting circuits R1 and Q1 with their respective threshold values to judge a disconnection and a short-circuit; and retaining circuits 10 and 11 for generating a signal and retaining the signal when the current value is judged as being smaller and larger than the respective threshold values as a result of comparisons by the corresponding comparing circuits 8 and 9. Thus, it is possible to indicate a fault in an LED indicating light to the outside while making the turning ON of an LED unperceivable.