1987 Chevy 350 Van. Cruise control inoperative. Where to start troubleshooting? Is there a replaceable switch within the steering wheel control that also houses the wipers?
2007-01-27 03:53:47 · 2 answers · asked by ? 1 in Cars & Transportation ➔ Car Makes ➔ Chevrolet
The first thing to check are the more obvious types of problems. Check the mechanical linkage that connects to the TBI unit on top of the motor to be sure it is there and hooked up properly. Then check the vacuum supply to the servo. There should be a ton of suction when running and a supply with the motor shut off as there is a canister to hold supply vacuum when the motor is shut off or in a low vacuum state of the motor to supply the cruise when needed. Just remove the supply hose at the servo with the motor not running and you should here a hiss as the vacuum vents. Then check the other big hose for being plugged with the brake not applied, it should hold vacuum with no brakes and be leaking vacuum with the brake switch applied as it is a dump valve. If all this is good, you will have to start checking electrical switches, power and ground which is usually easiest at the servo. Without a wiring diagram in front of me it will be hard to say exactly which wire is for what. You need a power and ground supply with the ignition on and the cruise switch off. You will need a power supply to the servo with the cruise switch on. You need a power pulse when the set switch is enabled and another when the resume switch is enabled. You will also need a power pulse from the brake switch when it is on to disengage the cruise. If all of this is okay and the speedo works, it is most likely the servo. The biggest problems with these was broken vacuum hoses or supply canisters, broken linkages, servos, brake switches, and the switch/wiring harness inside the column. Good luck.
2007-01-27 05:05:38 · answer #1 · answered by Deano 7 · 1⤊ 0⤋
The older cars work their cruise off of vacuum...Check the vacuum lines to make sure they are no cracked and corroded. If they're good, check the canister that holds the vacuum. If that is good, you're problem is more than likely electrical.
2007-01-27 04:00:40 · answer #2 · answered by Mark D 3 · 0⤊ 0⤋