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1995-2002 Range Rover P38A
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Discussion Starter #1
For the last 15yrs I have owned and driven daily a '99 4.6 HSE. I have replaced and repaired many parts over years but it is generally in pretty good shape. 225k on clock and still going strong.
Lately my cruise control dies after about 10 - 20 mins on road. Once it dies it won't start again while driving; and won't work again on day. I've arrived at destinations and left for up to 2 -3 hrs before starting out again. But unlike when first starting, the CC won't turn on at all.
It seems like when the engine heats up to normal running temp the CC won't work. My regular mechanic and an auto elec can find nothing wrong with the system itself. My mechanic suggests it may be a 'dry' solder joint on control panel; which loses connection when engine heats up.
I've looked through many many posts but haven't seen anything specifically related.

Anybody got any ideas?? The idea of locating a 'dry' solder joint on control panel doesn't sound feasible??
CityHog

P.S. On rough surfaces it has more rattles in it than a babies creche. Is this normal for an old P38A? Can rattles be fixed by removing interior panels and reinstalling with better seals and fixings?
 

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1995-2002 Range Rover P38A
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Mine was doing the same. I found that the problem was the brake light switch. With wear over time it got to the stage that the adjustment was so fine that once things got warm under the dash, and a little expansion occurred, it would act like yours. The cc disconnects as soon as the brake lights are activated.

I dropped the lower panel to get to the switch, bent the switch bracket a tad in the right direction so the switch operated a little later, i.e. instead of only breathing on the pedal you had to move it a couple of mm, no more problems, factory fresh again.
 

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1995-2002 Range Rover P38A
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Yeah I would start looking at all of the vacuum connections and inspect the rubber diaphragm on the actuator in the engine bay, along with the brake switch as mentioned above. From your description it seems like it may be losing vacuum slowly. I just replaced the rubber hoses in mine with silicone which will hopefully bear the heat of the engine bay better over time.
 

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JACK'S GRANDAD
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There are set testing procedures in RAVE for the cruise control. I would follow them first. I have found the culprit a few times doing so myself.

Martin
 

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1995-2002 Range Rover P38A
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When mine died it turned out to be the vacuum hoses at the back of the diaphragm.
Turned out they all had small cracks at the fittings. I tried a couple of things to clamp them but nothing worked until I replaced them.
Worked fine ever since. Well until the motor destroyed itself.
 

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1995-2002 Range Rover P38A
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When Dtoyne mentions the brake light switch, there are TWO different switches on the pedal. One is the brake light switch and one is the cruise control cancel switch which connects to the vacuum hose. It's got an o-ring and a spring in it. Take it apart and check it holds vacuum. I replaced all the hoses, including the ones on the diaphragm even though they looked OK. Works perfectly now. I'd start by replacing all the hoses.
 

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JACK'S GRANDAD
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Or you could start by doing the tests in RAVE......
 

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1995-2002 Range Rover P38A
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Discussion Starter #11
Thanks for advice guys. I'm still yet to take all this to my LR Whisperer. He has just recently replaced plugs and leads (and engine flush) and the old truck is now running like new: purring like a kitten. NEEDS TO BE POSTED FOR ALL!! He also replaced all O rings in EAS valve box. Now never been better to drive! BUT it leans heavily to passenger rear and front when parked for while.
So I just checked, it's been $9k spent (incl AC make good repair) since Dec 17: AND its been money well spent. Next tasks to prioritise; cruise control, new remote or suspension lean?? Decisions Decisions
 

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1995-2002 Range Rover P38A
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My cruise control isn't doing a good job of holding/maintaining speed (but I can hear it 'click' when I press the set button). I've checked for vacuum leaks under the bonnet and haven't found anything, so I'm thinking my next step is to check at the brake pedal?
 

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My cruise control isn't doing a good job of holding/maintaining speed (but I can hear it 'click' when I press the set button). I've checked for vacuum leaks under the bonnet and haven't found anything, so I'm thinking my next step is to check at the brake pedal?
The click you are haring is the cruise control ECU module Telling vacuum pump how much vacuum to supply to actuator to pull the cruise control throttle rod backward to meet the throttle to maintain the chosen speed.

You needed to replace three items under the hood after the fire for the cruise control to work properly. The vacuum pump, the Vacuum hoses and the actuator. The vacuum pump is located on the inner fender on the driver side, next to the evap box thingie... don't recall the technical name right now. The actuator has the vacuum diaphragm that connects to the cruise control throttle rod via a ball joint where the actuator and cruise control throttle rod meet separate the ball joint halves by pulling the throttle rod cup off the ball stud on the actuator. No special tool is needed because the actuator will be off it's mount already.

So is sounds like you cruise control is just kind of working. If you replaced the actuator with a second hand part the diaphragm may be leaking since you say you checked all the hoses.
 

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Discussion Starter #14
Took the truck for a 440k+ run on Sun. Just to really enjoy an EAS that's balancing beautifully AND to savour the sweet running 4.6; clearly one of life's great joys. Aaaah, when it's all working ....sorry, I was getting a bit emotional.
BUT I took to the road to also test the CC again. I had some faint hopes a decarbonated engine with new plugs would send different emissions to the CC, which would respond and bark back into life!! A slightly different idea to all above. And No it didn't pan out as hoped. Lights came on as they should, press the Set and .....nothing. The CC has died (or some part of)!!!! At the time of my post in late April the CC was clearly in it's death throes. But the light is still on and investigation by elec and mech give great hope.
So all comments above will now be reassessed in more detail in light of latest development. CC is a Must Have on the highway during these times of joy (see above), so right now, it's restoration to full and working life is Priority 1; which solves my dilemma noted in another post about where I would next focus
 
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