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Home >> BMW >> 1990 >> 735i >> Repair and Diagnosis >> Accessories & Equipment >> Cruise Control Systems >> Diagnostic Testing >> Step 2
July 1: So it begins. Don't worry, this is not in the correct legal jurisdiction!

Step 2

Turn ignition switch to ACC position. Measure voltage at connector X22 as in PIN VOLTAGE SPECIFICATIONS - TABLE 2  .

PIN VOLTAGE SPECIFICATIONS -

CONDITION MEASURE BETWEEN CORRECT VOLTAGE IF VOLTAGE IS INCORRECT
S28 Cruise Control Switch in NORMAL, RESUME and ACCELERATE/SET positions. 1 & Ground Battery Check wire from terminal 1 of X22 to fuse for an open/ See schematic in this article.
S28 Cruise Control Switch in NORMAL,RESUME and ACCELERATE/SET positions. 1 & 23 Battery Check wire for an open to ground. See Schematic in this article.
S28 Cruise Control Switch in NORMAL,RESUME and ACCELERATE/SET positions. 2 & Ground Battery Check S28 Cruise Control Switch. Check wire for an open. See Schematic in this article.
Move S28 Cruise Control Switch to OFF (Up or Down). 2 & Ground 0 Volts Check S28 Cruise Control Switch. Check wire for short to Battery. See schematic in this article.
Move S28 Cruise Control Switch to ACCELERATE/SET (Push away from driver). 4 & Ground Battery Check S28 Cruise Control switch. Check wire for an open or short to ground. See schematic in this article.
S28 Cruise Control Switch in NORMAL, OFF and RESUME positions. 4 & Ground 0 Volts Check S28 Cruise Control switch. Check wire for a short to battery/ See schematic in this article.
Move S28 Cruise Control Switch to RESUME (pull toward driver). 5 & Ground Battery Check S28 Cruise Control switch. Check wire for an open. See schematic in this article.
Move S28 Cruise Control Switch in NORMAL, OFF and ACCELERATE/SET position. 5 & Ground 0 Volts Check S28 Cruise Control switch. Check wire for short. See schematic in this article
(1) If measured voltages are as indicated, go to STEP 3  .
Fig 1: Wiring Schematic
G91F02916Courtesy of BMW OF NORTH AMERICA, INC.
Fig 2: Wiring Schematic (Continued)
G91H02917Courtesy of BMW OF NORTH AMERICA, INC.