cruise control

[jimsshuman]

anyone know how to troubleshoot the cruise controll system on a 91 RRC swb? would you mind sharing?
thanks

[Ed*]

one thing that goes wrong is the vacuum. Check the actuator to make sure its not cracked and the vacuum lines too. The actuator is in the engine compartment above the drivers side rocker cover on the back (closest to the firewall) it controls the throttle. I attached a photo of what the actuator looks like.


This is what was wrong on mine (acutuator was cracked and didnt hold a vacuum and one of the vacuum lines was also old and brittle and cracked[IMG]file:///C:/Documents%20and%20Settings/Ed/Desktop/IMG_6108.jpg[/IMG]

[MM17]

Cruise control malfunction

Check all the vacuum lines from that actuator to the vacuum pump that's behind the left headlight near the intake snorkel. Insure all lines are good - no leaks. Use a MityVac to suck the throttle actuator - does it work? Will the actuator hold the throttle in an open position? If not, you have a bad actuator or leak - or both. You can use the vac gauge on the MityVac or another gauge to check for vacuum form the electric pump. Hot wire 12v. directly to the pump motor to make it run and see if it sucks. Then connect the vac line to see if it'll make the actuator open the throttle. Will it hold the throttle open? If all that works, it is probably electrical. Make sure the wires are connected to the pump - the connectors get sloppy and sometimes the wires crack out of the connectors. Check your speed transducer wires - underneath the vehicle on the left side follow the speedo cable from the gearbox to the frame - the speed transducer is between that short speedo cable and the longer one that goes up to the speedo binacle.

[pvkd]

Another problem is the Cruise ECU.

Test:

Run the engine - all doors and windows closed.
Turn off and within 30 seconds try to open the sun roof or a window.
If it works with the ignition off - its not a bad cruise ECU
If it does not work - you have a bad Cruise ECU - out host sell for about ~$200

The reason is that the cruise ECU also controls the delay for the sun roof and the windows after the ignition is turned off (but before a door is opened).


Paul

[MM17]

cruise ECU

Paul - Do you know if that cruise ECU check hold true for an '88 RR?

[pvkd]

I don't know...check with our hosts.

[jimsshuman]

thanks guys, looks like i now have something to work on the rest of this beautiful afternoon.