CUSTOM CRUISE III TROUBLE SHOOTING/DIAGNOSIS
Model and Year 1984 CAPRICE, IMPALA, CAMARO, MONTE CARLO, CELEBRITY, EL CAMINO, CORVETTE, CAVALIER, AND CITATION
CONDITION CAUSE CORRECTION --------- ----- ----------- Inoperative No power to module Check fuse, brake and System terminals "G" and "A". clutch switches, turn signal handle, pinched wires in steering column.
Open "ground" at Repair ground circuit, module terminal "J", (run new ground if servo terminal "C", necessary). or VSS ground.
Open SPS circuit Repair leads and/or (module-servo leads replace servo. F-B, H-D or SPS coil in servo).
Vac release valve Adjust or replace circuit open to vacuum release valve, atmosphere. check hoses, or repair circuit.
No high and low volt- Check for open leads age signal at module or bad buffer amplifier speed sender terminal or speedometer. Check "D". ground and B+ input.
No 12 volt signal at Check for open lead or module "set/coast" connector or bad turn terminal "L". signal handle. Check for terminal in proper cavity.
Inoperative No vacuum at small Check for plugged, System hose to servo. pinched, disconnected vac hoses, incorrectly positioned 3 way check valve, restricted engine vacuum fitting.
Cocked servo posi- Replace servo. tion rod and spring.
Leaky servo and/or Replace servo. inoperative valves.
Disconnected servo Reconnect linkage.
Inoperative module. Replace module.
Vehicle Surges Excess slack in Adjust. servo linkage.
Dry speedometer Lubricate. cable.
Spikes on B+ lines. Find cause and repair.
Turn signal or other Reposition electrical electrical device leads away from cruise interference. or VSS buffer leaks. Check for poor ground at module, servo, or VSS buffer.
Restricted (kinked Inspect hoses and re- or leaking) vacuum position as required. supply hose to accumulator or servo.
Crossed vac and vent Rewire. electrical leads between module and servo.
Binding servo Bowdin Replace. cable.
Torque converter Normal (not a cruise clutch cutting in problem). and out.
Vehicle Surges Intermittent ground. Check for poor ground at servo, module, VSS buffer. (Generally this is a common ground at the I.P. or servo.)
Servo valves stick- Replace servo. ing.
Inoperative module. Replace module.
Cruise Set Excess slack in Adjust. Speed High or servo linkage. Low Incorrect module Make correction. part number usage.
Inoperative module. Replace.
No Resume Incorrect operator Advise operator. Function technique. (If R/A held down for more 1 second, system re- verts to accel mode. Speed at time of re- lease is new cruise speed.)
Open connection at Repair. terminal "A" of module or terminal in wrong cavity.
No "Tap Down" Incorrect operator Advise operator. Function technique. (Tap down held down in excess of .4 second.)
Incorrect module Make correction. usage.
Vehicle Cruises Crossed vac and vent Rewire. or Resumes wires. Beyond Set Speed Inoperative turn Replace. signal mode control switch.
Vehicle Cruises Sticking valves in Replace servo. or Resumes Be- servo. yond Set Speed Binding throttle Make correction. linkage.
Inoperative module. Replace module.
Incorrect module Make correction. usage.
Inoperative speed Replace buffer. sensor buffer.
Cruise Drops Inoperative module. Replace module. Out While Tapping Down
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.
