Cruise control stops working - D1

[dhuddleson]

Just this past week my 98 D1 cruise control started acting up. I use it for my 15 mile cruise on the expressway each day to and from work. One morning late last week, the vehicle suddenly dropped off cruise, but pressing RESUME worked as expected. That afternoon, the cruise would not work at all. At home I did a quick diagnosis and found the vacuum hose split right at the cruise unit near the throttle linkage. I snipped off the split section, and reconnected. Problem solved! WRONG! Now I am finding that on some "outings" the cruise works fine, other times it does not work at all, and at least one journey it worked for the first 15 minutes and then not again for that whole day....

Any suggestions on where to go next? No other strange behaviour on the vehicle (well, other than being a Discovery...). Why does it seem fine at times, and then completely "dead" at other times?

 

[Jparker]

Mine's the exact same on my 97 RR. Since I spend a lot of time on the highway, I finally took it to a dealer to have it fixed. It worked perfect for a while, until I took it off road. Now its back to working some days and sometimes not. It only cost about $50 at the dealer to get it fixed.

 

[Peter-man99]

My 99 D1 has been doing the same thing. At first I thought that it may be some of the wiring in the cruise on off button. I took that out and it appeared that all the connections and wires seemed to be in good shape. The next time I used the CC it worked fine but that didn't last that long. I guess I will look at the vacuum tubes to see if there is anything there.
John, when you take it to the dealer do they replace the whole unit or just service it?

Peter

 

[dhuddleson]

John,

We are all curious now to see if you have a listing of what was done or part #'s which were replaced... this AM my cruise would not engage at all. Usually you can hear a relay engage somewhere either in the console or dash (passenger side?). But when it malfunctions, no audible "click". So what happened this AM???? It starts to work when I tried it just less than 5 miles from work!!! Arrrggghhhh!!! Why?

 

[jmonsrvr]

did you check all of your hose connections? check the connection behind the brake pedal.....also make sure the plug is plugged in nice and tight on the actual ac pump...

 

[RoverChic]

My cruise did the very same thing on the 1998 D1. I checked the brake switch, then I just decided to replace all together. The problem is solved as of now. Should be Part # ERR 2622. Hope that this helps!
Melissa

 

[Joey]

When my Cruise started to act up. I order all new silicon vacuum line and replaced all the lines in the Disco took about 30 minutes. I even pulled out the vacuum pump and made sure that the 2 small lines on the pump itself were in good shape (of course I had ran out of slicon by then) I got a real nice kit from summit racing for $30, it even had enough to change the 2 valve cover vent lines look real pretty in bright red too.

 

[Hoot]

check the brake pedal switch.

i know someone already mentioned this but i had the same problem where it would work then it wouldn't work, then it would, etc.... i replaced a bunch of spliting vacuum hoses but the problem still persisited. then i pulled of that plastic dust cover above the driver side footwell and careened my head around and sure enough the CC brake switch was halfway falling out of its correct position.

It is sort of a crappy design that allows it to dislodge fairly easily. The switch mechanism is not hard fastend in. It is just held in place by inserting the mechanism into a notched hole in a steel bracket and giving it a half turn.

for half of you having problems i bet this is the problem. check it out, you have nothing to lose. You may end up with a crick in your neck, but if it solves your problem it is better than that pain in the ass the CC switch was giving you.

 

[dhuddleson]

Hoot,

I'm going under the dash next. I had one split vac hose right at the actuating mechanism, and repaired that. I have examined "pump" at left front corner and the vacuum line all the way to the bulkhead/firewall. Everything in the engine compartment related to the cruise seems fine. I'm hoping that switch at the brake pedal is the issue, whether seated incorrectly or non-functional...

 

[dhuddleson]

I think I have narrowed down the cruise control problem to under the dash. While driving yesterday afternoon, I used my left leg to kick and prod the brake pedal while driving at a constant speed (about 60 mph). I was attempting to make sure the pedal was completely UP and that maybe the switch itself was in position correctly.

Initially the cruise control "SET" button would not activate anything, then suddenly... it worked! So, it must be related to the switch (ERR 2622) under the dash. Is it faulty, or is it poorly located? Some time at the weekend will hopefully reveal all! Wish me luck to solve the mystery.