Thread: Cruise control

possibly a split in a pipe, i could be wrong here but i was under the impression that they might work of the vacuum advance in a diesel.......(or what ever it is called)

Check the brake switch too.
If it's loose or not set right, the cruise can think the brakes have been applied.

Mine was doing similar, only engaging very occasionally and when it did it would most often drop off after a few minutes.

Had a look at it over the weekend, problem was with the vacuum pipe that went from the bottom of the cruise control pump round to the bellows was completely perished and cracked. Not surprised since that area gets very very hot with the heat from the exhaust so the tubing has a very hard life.

$3 worth of replacement vacuum tubing to replace the length of pipe and job's a good'un.

If yours is cracked/leaking too it may be worth avoiding using cruise till you find the leak and fix it, forcing the pump to work to maintain a leaking vacuum could cause it to burn out prematurely possibly, thus leading to a more expensive fault than a bit of tube.

Cheers

Al

Originally Posted by Sharky

G'day, just a quick question my cruise control sometimes engages and works fine and other times it will be working then dis-engage on its own or won't engage cruise control at all.
Just interested if anyone else has had similar problem and where to hunt my intermitent fault to, any info would be appreciated thanks

if its a disco, drop the panel under the steering column (2 plastic screws).
towards the top of your brake pedal you will see a brake switch with a 3 wire plug going into it.

the switch has 2 functions. when you push the brake pedal it

1. joins the brake light circuit (the two outer connectors)
2. brakes the cruise control circuit (one outer and one innner connector - cant remember which outer one).

To remove the switch, disconnect the wiring lead plug and then twist the switch anti-clockwise by 90 degs and it will come out.

The plunger on the switch is self calibrating, push it in firm and then pull it out firm, you will hear it click as you push it in and then pull it out.

Reinstall by pressing the brake pedal down to floor, remount the switch in the same way you removed it, the release the pedal. as the pedal returns to its normal resting position you will hear it pushing the plunger into the correct resting position.

This should fix your problem, otherwise the switch may need cleaning/replacing. Brake light switch failure is a known issue with the disco - i replaced mine 3 days ago. The switch should be had for about $50 new.

Generally however, its just that the switch plunger is disengaging when u go over bumps and causing the cruise to think you are pushing the brake pedal.

Andrew

Originally Posted by Sharky

G'day, just a quick question my cruise control sometimes engages and works fine and other times it will be working then dis-engage on its own or won't engage cruise control at all.
Just interested if anyone else has had similar problem and where to hunt my intermitent fault to, any info would be appreciated thanks

Mine did this for a while - turned out to be a dodgy control unit in the end but it wasn't helped by having a leaking piple on the vacuum advance either so check the hoses and the brake switch (as mentioned above).