Hi all, first post and a very useful one to all I hope!
(It is a long one but worth the read)
There are lots of cruise control failures on WK/WH models but no solid fixes found as of yet.
The majority point to vac issues, pinion factors and the like but the problem is somewhat easier, simpler and cleaner to fix!
I had cruise failure and it drove me nuts, it wouldn't engage, would randomly drop off while working and also disengage when trying to set the speed.
so I have to share this one as I bet there are many more experiencing the pain I have!
- Root Cause of Fault -
Poor electrical connections at cruise switch on steering wheel.
- Rectification -
1. remove the switch, this can either be done my taking the steering wheel airbag & switch centre part off by undoing the nuts at the rear OR if you are heavy handed like myself get your fingers behind the steering wheel centre/cruise switch end and bend it forward to you so you can see the back of the switch where the wires connect to it.
(Objective = get the switch out!)
2. undo the 2x tiny torx screws, unplug the wiring to the switch & lift the switch out of the steering wheel.
The switch is pretty rebust so dont worry to much about crushing or snapping it. (but if you do its your own fault!)
3. now the switch is out take it in home, there are only 4 parts to the switch and it is really basic to take apart, just be gentle with it, start with the switch facing you (so you can see the text), If you look on the centre line where the switch rocks you will see a small lug on each side, these lugs do not go all the way through, the rocker switch just snaps into them, get a small screwdriver/knife or something of that nature and pry the rocker button off from just below or above the lugs.
It should pop off pretty easy, put it to one side and keep it safe.
4. you will now see the rubber insert with 4 small circular bits sticking up, ALSO at this point flip the switch over, you will see 3 bits of rubber on the back, one at the bottom corner which is pretty big and flappy, and 2 small bits in the kinda centre of the switch, now then, get small screwdriver and poke the little bits inwards gentley (but not all the way), then poke the big flappy bit through gentley.
Flip the switch back over so you can see the front and SLOWLY peel the rubber out from the switch recess. put it to one side and keep it safe.
5. Now you will be faced with a circuit board, looking from the front of the switch in the bottom right hand corner you will see 3 large silver(ish) solder circles, flip the switch over and you will see the 3 electrical pins that connect to the steering wheel wiring. The plan is to remove the circuit board from the switch housing and NOT brake the pins off!
Look at the switch from the front, you will notice the two black melted lugs holding the circuit board to the plastic housing, remove these. I used some long nose pliers and twisted them until they sheared off level with the top of the circuit board, you could use whatever you like, just be gentle and don't damage the circuit board!
When you have twisted the lugs off flip the switch so you are looking at the back, you will see the 3 pins in the wiring recess locator DO NOT PUSH FROM HERE! LOOK at the centre of the switch, you will see on the left and right about half way up the back of the circuit board, apply a small amount of gentle and even pressure on each side, one at a time and the circuit board should fall out of the housing.
6. THE ROOT CAUSE!
the 3 small pins sticking off the circuit board!
poor connection to the ecu loom results in cruise failure, the WH/WK has a fly by wire throttle on the CRD model, and I guess that the V6 & V8 models must be the same as the cruise fault extends to all WK/WH models thus indicating that these switches and the system behind the control are all common.
I cleaned the 3 pins with Acetone, and I also used a sharp knife to skim the surface clean, then acetoned again, finishing off with a wipe with kitchen roll!
While the switch was in bits I also Acetoned the gold contacts and wiped with kitchen roll.
7. Reassemble the switch, its pretty straight forward now you've taken it apart!
8. Reinstall on the vehicle. (I would do it loosely, take it for a test drive, it should engage cruise without going anywhere) if it works finish the refit and you're done.
9. IF it doesn't work... I would look towards the opposite switch (possible same problem) OR speed sensor OR defective parts on the circuit board OR possilbe brake light switch.
Hopefully though it is just the same fault as mine (crap electrics!)
Finally, if you get exceptionally stuck I have pictures of the whole process, drop me a PM and I will email over!
Best of luck folks!
(Approved Electrician & PLC Programmer)