9 replies to this topic

[JimWWhite]

Last fall I began having problems with my '94 850's cruise control in that it would disengage when going down the interstate. Normally it would not reengage immediately. Usually after a couple of miles I could get it to reengage when I clicked the button, but sometimes not. Sometimes it would stay engaged and sometimes it would drop back out after only a mile or so. I took it to the dealer in Winston-Salem and they said it was the ignition switch and they replaced it. They checked the vacuum lines everything else in the process and that was their diagnosis. Worked fine for a few days but started to malfunction again. Then it suddenly started to function correctly before I could take it back in. All winter long I used the cruise control every day and it probably only disengaged maybe twice in the past four months. And usually only on warm days. Now that the weather has warmed back up here in NC it is started to malfunction again. In the mornings when it's cool it works properly. But in the afternoons if it's been hot it will disengage and refuse to stay engaged. It's acting exacly the same way as it did last fall before taking it in to the dealer.

Has anyone else had problems like this? Any ideas? Again, they say they checked out all the components including the pedal switches, vacuum lines, and the control unit itself.

Any insight or help would be greatly appreciated before I have to take it back in again.

Thanks!
Jim White

[kenhoeve]

if the vacuum lines, control unit, vac pump, and bellows are ok, which the dealer said they are, then the only thing it could be is a faulty circuit in the tree on the steering column.

i would try the control unit first. you can pick one up for $30 or so. then try a new stalk on the steering column. not sure on cost, but pretty cheap from recycler.

[merlin390]

i would stick my own head underthere and make sure the vacuum lines are not cracked/dry rotted. spray some contact cleaner and dielectric grease into the hardshell connector.

[UberV70]

Underneath the dash is the control unit for the cruise control. Last summer i was getting some alarm work done and i guess the guy working under there knocked the switch that controls the cruise, all i had to do was re-set it and i was good to go. From your problem it sounds like it MIGHT be that the switch is loose / breaking.

Just something else to check before you go and blow more money at the stealership.

[850-Turbo]

Underneath the dash is the control unit for the cruise control. Last summer i was getting some alarm work done and i guess the guy working under there knocked the switch that controls the cruise, all i had to do was re-set it and i was good to go. From your problem it sounds like it MIGHT be that the switch is loose / breaking.

Just something else to check before you go and blow more money at the stealership.

Isn't there another electrical switch connected to the break pedal (like in the old days)? That's how you can disengage cruise control (is this the same as the switch you're refering to, under the dash?).

I would suspect that if the switch is loose, or defective, a slight bump will cause CC to disengage and may take another bump to causes the switch to make contact again, before CC will engage again.

[ccsct203]

try pulling UP on the foot brake with your toes while driving and engage the cruise at the same time while driving.

[JimWWhite]

Underneath the dash is the control unit for the cruise control. Last summer i was getting some alarm work done and i guess the guy working under there knocked the switch that controls the cruise, all i had to do was re-set it and i was good to go. From your problem it sounds like it MIGHT be that the switch is loose / breaking.

Just something else to check before you go and blow more money at the stealership.

OK, what am I looking for under the dash? Can you describe it or give a little more specifics of where I can find it?

Thanks!
Jim

Isn't there another electrical switch connected to the break pedal (like in the old days)? That's how you can disengage cruise control (is this the same as the switch you're refering to, under the dash?).

I would suspect that if the switch is loose, or defective, a slight bump will cause CC to disengage and may take another bump to causes the switch to make contact again, before CC will engage again.

It doesn't seem like a bump causes it to disengage. I've had both switches replaced on the brake pedal in the past year. And I've tried to use my toe to pull up on the pedal before setting the cruise but that doesn't seem to work either. As I mentioned in my original post when it disengages I generally cannot get it to reengage immediately. If I wait a mile or so and try again it will sometimes reengage. But then again, sometimes it won't. And usually when it disengages it keeps doing it all the way home.

[850-Turbo]

It doesn't seem like a bump causes it to disengage. I've had both switches replaced on the brake pedal in the past year. And I've tried to use my toe to pull up on the pedal before setting the cruise but that doesn't seem to work either. As I mentioned in my original post when it disengages I generally cannot get it to reengage immediately. If I wait a mile or so and try again it will sometimes reengage. But then again, sometimes it won't. And usually when it disengages it keeps doing it all the way home.

I still wouldn't dismiss the possibility of something intermittantly connecting/disconnecting. THere are 2 thing that I know of that would shut off the CC. One of the break pedal switchs and the main ON-OFF switch on the control lever. There may be more, like on a clutch pedal for manual trans.

Next time you're able to get CC to work, try tapping or wiggling the turn signal lever (if that's where yours is). See if you can cause it to disengage.

If you find the control module under the dash, check the connectors. If you have intermittant break or shorts between the unit and the control lever, that may cause problems as well.

Also, there is a transducer to sense the speed(maybe near the half shafts on the transaxle???). If you can locate it, at least check that nothing is damaged or have corroded electricals.

[JimWWhite]

I still wouldn't dismiss the possibility of something intermittantly connecting/disconnecting. THere are 2 thing that I know of that would shut off the CC. One of the break pedal switchs and the main ON-OFF switch on the control lever. There may be more, like on a clutch pedal for manual trans.

Next time you're able to get CC to work, try tapping or wiggling the turn signal lever (if that's where yours is). See if you can cause it to disengage.

If you find the control module under the dash, check the connectors. If you have intermittant break or shorts between the unit and the control lever, that may cause problems as well.

Also, there is a transducer to sense the speed(maybe near the half shafts on the transaxle???). If you can locate it, at least check that nothing is damaged or have corroded electricals.

The transmission is an automatic. I'll check out the stalk by tapping, etc. on it this evening when I go home. Now, when I'm down on my knees looking under the dash for the control unit, what am I looking for? Can you describe it or where it is? Are there any lines or connectors that I'd be looking for to identify it?

Jim

[andrew_the_fox]

try pulling UP on the foot brake with your toes while driving and engage the cruise at the same time while driving.

^ ^ that was my first thought possibly the brake pedal itself or even something mechanical. if the slightest amount of pressure is put on the brake cruise control automatically disengages.

That is weird tho that it only seems to be warm temps. But I definitely agree try cruise control with your left foot pushing the brake up wards. see if that holds up.