TM 9-2320-360-20-1 WARNING Jewelry can catch on equipment and cause injury or short across electrical circuit and cause severe burns or electrical shock.  Remove rings, bracelets, watches, necklaces, and any other jewelry before working around HET Tractor. WIRE NO. 1712 VOLTAGE TEST (1) Turn ENGINE switch to ON position. (2) Place positive (+) probe of multimeter on wire no 1712 at ENGINE BRAKE RETARDER ON/OFF switch. (3) Place negative (-) probe of multimeter on ground and look for 10-14 volts on multimeter. (4) Turn ENGINE switch to OFF position. CIRCUIT BREAKER TEST (1) Remove eight screws and panel from console. (2) Turn ENGINE switch to ON position. (3) Place positive (+) probe of multimeter on lower terminal of circuit breaker. (4) Place negative (-) probe of multimeter on ground and look for 10-14 volts on multimeter. (5) Turn ENGINE switch to OFF position. WIRE NO. 1715 VOLTAGE TEST (1) Remove wire no 1715 from connector on right cylinder head. NOTE Wire No 508 is for DDEC II vehicles, wire No. 988 is for DDEC II vehicles. (2) Remove wire no. 508/988 from ENGINE BRAKE relay. (3) Install jumper wire from terminal 85 on ENGINE BRAKE relay to known good ground. (4) Turn ENGINE switch to ON position. (5) Place ENGINE BRAKE RETARDER ON/OFF switch in the ON position. (6) Place ENGINE BRAKE RETARDER HI/LOW switch in the HI position. (7) Place positive (+) probe of multimeter on wire no 1715 at right cylinder head. (8) Place negative (-) probe of multimeter on ground and look for 10-14 volts on multimeter. (9) Place ENGINE BRAKE RETARDER ON/OFF switch in the OFF position. (10)   Turn ENGINE switch to OFF position (11)   Remove jumper wire from ENGINE BRAKE relay. (12)   lnstall wire no 508/988 on ENGINE BRAKE relay. (13)   lnstall wire no 1715 on connector at right cylinder head. Change 3  2-591