Cruise control keeps cutting out - no CEL

[pulse69]

Hi,

Just bought a Gen 4 liberty wagon. Love it so far but have come up with a couple issues which I cannot find much information on. Maybe you can help.
When I turn on Cruise control and set a speed, it controls the speed for 0-10 seconds then turns off. No error codes or anything come up, it just stops controlling the speed as if the set had been cancelled.

Any help fixing this one would be appreciated.

Marty

[Hotwire]

I'm thinking faulty brake lights / globe causing the ECU to think the brakes are applied and therefore cutting cruise control. Check/replace all brake globes perhaps as a cheap starting point?

[Mat04]

Mine does the same unless its in 5th gear.

[pulse69]

i keep thinking there must be a short somewhere in the clutch pedal switch or the brake system. i dont know the best way to check. Guess I'll get my multimeter out.

it seems to happen in all gears.

[pulse69]

Checked the clutch and brak switch. I think the issue is in the Neutral posistion switch. I heard that a fix is to take it out of the gearbox, grind the copper crush washer down and then put it back on.

How do you grind down a washer?

[bigBADbenny]

you could probably use medium fine sandpaper on a flat surface, rub the washer gently on it as copper is very soft.

[pulse69]

I'll give it a go.

[pulse69]

Ok, it took a while but I finally got around to fixing the cruise control.

The neutral safety switch was not working. This is the rearmost switch on the left had side of the gearbox. I took it out, grabbed the sealing washer, beat it flatter with a large hammer (it very soft) then put it back in. I made certain that the switch is still sealing properly by nipping it up nice and tight. All is working now. Very happy for a zero cost fix.

P.S. the workshop manuals are excellent when it comes to diagnosing problems.