Cruise control not working

[Alex121]

Hi all,

Bit of an odd one and I'm running out of ideas..

My cruise control has been working intermittently recently, most of the time it wont work, the cruise text always displays on the dash when I turn it on but that's it. Occasionally though, I can turn it on, flick the switch at the end of the stalk and it'll work fine for 10 minutes or so before cutting out and losing speed.

Gatos kindly lent me a cruise control kit to troubleshoot with (thanks Alex) and tonight I swapped out the cruise control ECU, pedal switches, indicator stalk and vacuum pump for the bits he sent me and it still didn't work. I managed to get it to work once but that was it.

There are no leaks in the tubing from what I can tell + if there was it wouldn't work spot on occasionally.

I've not changed the vacuum thing behind the accelerator pedal that controls it yet as that's a b*tch of a job and I don't think it's that tbh.

Any ideas anyone?

Thanks

[gatos]

Oh dear..... I was hoping that one of the things I sent you would sort out your problem. Have you checked that all the brackets holding the CC cut-off switches are tightened and not loose by any chance. Also, I am not sure if you are aware, but the small shaft on the cut-off switches can be adjusted. What I normally do, is pull the shaft to the max position and then let the pedal return to it's resting position, which will push the cut off switch shaft back to the correct position.

Another thing to check, is the servo thingy that pushes the accelator pedal. It can also be adjusted, so make sure it is in the correct position, or that the "screwy" bit has not turned and is not loose.

Other than that, it could either be some loose or corroded wiring, or a long long long shot, a dodgy CEM. Double check the connectors to the CEM to make sure they are secured properly.

[Alex121]

I did check the wiring and it all looks fine.

Could you confirm which way the wiring connector on each of the switches plugs in? I'm pretty sure I got it the right way around but stupidly forgot to take a photo of it before removing the old one.

I'll have to have a play with that annoying spring thing behind the accelerator tomorrow. I hated installing that thing

[Bosstang]

Sometimes my cruise doesn't engage when I activate it and I found it was the switch on the clutch pedal, it needs adjusting so when the pedal is up it clicks the switch.
To get around this I just lift up under the pedal with my foot and then it clicks the switch and the cruise works again.

[Alex121]

Hmm interesting, I'll have a look at that tomorrow too, thanks.

It's odd though because I took my switches out and swapped them out for a different pair so I thought that may have fixed it if that was the issue. I'll give it a go anyway though, thanks

[gatos]

Originally Posted by Alex121

I did check the wiring and it all looks fine.

Could you confirm which way the wiring connector on each of the switches plugs in? I'm pretty sure I got it the right way around but stupidly forgot to take a photo of it before removing the old one.

I'll have to have a play with that annoying spring thing behind the accelerator tomorrow. I hated installing that thing

It does not matter which way the connectors go, so I would not worry about that. I will have to agree with Bosstang about the switches. They are most probably the reason of why the cruise does not engage. Even the slightest push of the pedal disengages the CC, so if the switches are not positioned properly (I mean the shaft actually that can be adjusted), then it may be very likely that one of the switches either lets air go through or cuts the electric circuit, stopping the CC from engaging.

[Alex121]

How does the system actually work?

Would a problem with anything to do with the ABS cause an issue? How does it maintain speed? is it through speed or revs?

How do you adjust the switches on the pedals? I couldn't see anywhere to do it?

[gatos]

Originally Posted by Alex121

How does the system actually work?

Would a problem with anything to do with the ABS cause an issue? How does it maintain speed? is it through speed or revs?

How do you adjust the switches on the pedals? I couldn't see anywhere to do it?

This is not official, but rather my understanding of how the CC is working on our cars.
The vacuum pump creates a vacuum which moves the servo thingy on teh accelerator pedal. By pressing either of the brake or clutch pedal cut-off switches shaft thingies, you open the vacuum system which instantly stops the CC operation and also an electrical signal is sent to the CC ecu box to disengage the CC. Take on of the cut-off switches you removed from your car and try pulling the shaft thingy. Then try pushing it all the way in. It will make sense once you try this. When you install the cut-off switch on the pedal, you should extend the shaft all the way and when the cut off switch is n place, just let the pedal rest back to it's original position and if necessary pull it with your hand so it can push the shaft to it's correct position.

Not sure if an ABS fault would affect the CC or not. I had some issues with my ABS recently and it had no effect to the CC, but then again, my CC setup is completely different to yours

[Alex121]

Thanks Alex,

I'll give this a go in the morning before work

[Alex121]

Pulled the switches right out and let the pedals slowly push them in.

Still didn't work at all during my hour long commute this morning