Cruise Control Won't Set and not the pipe off.

[Darren]

Hi guys,

I have been through all the threads and not found the same problem...

My switch works fine and lights up at the 1st press and has never been a problem, pipe is connected and checked with no damage etc...the cable has been checked and not too tight or slack.

The cruise says it is set (cruise set in green) on the dash but the car does not maintain speed. Resume resets but again does not actually maintain the speed.

Any thoughts wouold be welcome as my head is now sore from scratching it!

Regards,
Darren.

[92 SVX]

Originally Posted by Darren

Hi guys,

I have been through all the threads and not found the same problem...

My switch works fine and lights up at the 1st press and has never been a problem, pipe is connected and checked with no damage etc...the cable has been checked and not too tight or slack.

The cruise says it is set (cruise set in green) on the dash but the car does not maintain speed. Resume resets but again does not actually maintain the speed.

Any thoughts wouold be welcome as my head is now sore from scratching it!

Regards,
Darren.

sounds like a weak vac diaphragm.

[Conn SVX]

You do feel it engage or not ? You say does not maintain speed. So u r driving along at 60MPH you engage cruise and take you foot off the gas and the car stays at 60 ? Or the car slows down? If you drop it back to 50 and hit resume what happens?

[Darren]

It does not engage at any speed although it says on the dash it is set.

[icingdeath88]

Originally Posted by Darren

It does not engage at any speed although it says on the dash it is set.

Ok there are basically 4 parts to the cruise control.

The controls - the button and steering wheel switches. These seem fine.

The control module. This must be at least partially working since the lights and buttons and switches do stuff, but could still be suspect.

The diaphragm/throttle cable. As 92SVX suggested, the diaphragm could have a leak and be unable to maintain the vacuum at all. Not sure how to test that theory though.

The vacuum pump. It's under the fuse box. The only way I can think to test it is to hook up a vacuum gauge to the vac line when you set the cruise control and see if it produces a vacuum. Since it's an electrical pump, I could see it failing, even if no one's seen it happen before.

The "usual suspect" vacuum line that connects the vacuum pump to the diaphragm, is partially hidden under the fuse box as well. It's very unlikely but it could have a leak or have come loose from that end if someone was working in that area of the car or something.

So that's all I can think of.

[Conn SVX]

Could it be a faulty drake light switch? The cruise lights remain on when you apply the brake . You can not engage the cruise with your foot on the brake. My guess is the switch. It was the culprit on my motorcycle .
Good news is it won't cost you much to check it out.

[icingdeath88]

Originally Posted by Conn SVX

Could it be a faulty drake light switch? The cruise lights remain on when you apply the brake . You can not engage the cruise with your foot on the brake. My guess is the switch. It was the culprit on my motorcycle .
Good news is it won't cost you much to check it out.

That is a good idea, and very easy to check. If the brake switch is bad, then the brake lights will be on.

[Conn SVX]

If the switch is shot then the switch won't trigger the cruise. Not sure if that is true or false.

[Darren]

I am going to try to get hold of the part with the cable and pipe and try that first then the pump.

The brake light switch is fine. It does not seem to be electrical as it's doing everything it should be just not mecahically setting and holding the speed.

Thanks for the input but I guess it's just going to be one of those replace parts and find the issue :-/

[Uncamitzi]

Originally Posted by Darren

Hi guys,

I have been through all the threads and not found the same problem...

My switch works fine and lights up at the 1st press and has never been a problem, pipe is connected and checked with no damage etc...the cable has been checked and not too tight or slack.

The cruise says it is set (cruise set in green) on the dash but the car does not maintain speed. Resume resets but again does not actually maintain the speed.

Any thoughts wouold be welcome as my head is now sore from scratching it!

Regards,
Darren.

there's a light on the dash? the button light is all I have.

[icingdeath88]

Originally Posted by Uncamitzi

there's a light on the dash? the button light is all I have.

Me too, I'm assuming the JMD ones are different.

[ensteele]

There is a fitting on the firewall that sometimes comes off. Check the vaccume line and see if it is disconnected. That is usually the problem. Everything else looks good, but no vaccume, and no worky. Check that.

[Darren]

I didn't know all SVX's didn't have the "cruise set" display at the bottom of the speedo with the warning lights, we still have the cruise switch which lights up orange when pressed.

So you guys can only feel when your cruise control is set and engaged???

Earl, it's not the pipe off of the actuator or split anywhere, that was the first thing I checked on.

I can only think it is a low vac issue either with the actuator or the pump.
The parts are very hard to find over here used so I will wait until another car is being scrapped and buy both parts.

It's not a big issue not working but if it's fitted I want it working

[icingdeath88]

Can you take pics of the light on the dash? So we know what we're missing out on?

I'd expect that the USDM parts would swap over, except for maybe the control module (considering the extra light on the dash). You could try and get them from over here.