Disco 2 TD5 retrofit Cruise control problem

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aribeiro

aribeiro

Member
Posts
37
Location
Portugal
Hi,
some months ago i retrofit in my 2000 2.5 TD5 the required switch(dash and steering wheel) and hopping it would work...it didn't.. :(
I made some investigations with nanocom to check the possible problems:
Brake switch: not ok but was replaced by new one
Clutch switch: not ok but replaced by new one
Cruise control switch: OK
SET switch: OK
RES switch: OK

It continues to not work... Any hint?
 
Hi, I didn't have any problem when I fitted mine -plug & play. You do need to make sure the brake and clutch switches/fuses are actually working.
Electrical wizzards will be along soon.
Griff
 
aribeiro said:
Hi,
some months ago i retrofit in my 2000 2.5 TD5 the required switch(dash and steering wheel) and hopping it would work...it didn't.. :(
I made some investigations with nanocom to check the possible problems:
Brake switch: not ok but was replaced by new one
Clutch switch: not ok but replaced by new one
Cruise control switch: OK
SET switch: OK
RES switch: OK

It continues to not work... Any hint?
Click to expand...
Hi. How did you realise that those switches which you replaced were not OK and how do you kow that theyr's inputs are getting well to the ECU now? Are the inputs showing OK with diagnostic tool? if yes the horns are working? Strangely the horn relay is involved too.
 
sierrafery said:
Hi. How did you realise that those switches which you replaced were not OK and how do you kow that theyr's inputs are getting well to the ECU now? Are the inputs showing OK with diagnostic tool? if yes the horns are working? Strangely the horn relay is involved too.
Click to expand...
Before changing the clutch and brake switch i checked with nanocom diagnostic tool. I was pressing the pedals and no status was changing in the tool (compared with another TD5 and on the other car was changing the status).
After swapping for new parts i could test again with nanocom.. i need to do it.
Stop lights are OK.
Horn is OK.
One strange thing is i measure today the voltage in the clutch switch and i never have the 12V there... i believe its not normal...
 
You have to check the brake and clutch switch inputs with nanocom to make sure, for the brake switch the N/C contact is important for cruise control not the N/O which works with the lamps... there is a mess with the clutch switch description cos IMO it might not be necessary to get 12V there as it closes to earth.
 
sierrafery said:
You have to check the brake and clutch switch inputs with nanocom to make sure, for the brake switch the N/C contact is important for cruise control not the N/O which works with the lamps... there is a mess with the clutch switch description cos IMO it might not be necessary to get 12V there as it closes to earth.
Click to expand...
Since i dont own a nanocom, i try to do as much as possible without it. if required i need to travel 50km to use one from a friend.
Regarding the clutch switch, one thing i tryed was to run with unplugged sensor and with a short circuit in the plug and the behavior is exactly the same.
I saw in rave that 12V are supplied to the sensor.. but since im newbie in this stuff, im not sure :)
 
aribeiro said:
one thing i tryed was to run with unplugged sensor and with a short circuit in the plug and the behavior is exactly the same.
Click to expand...
Then there's a problem on that circuit, try to hook a wire from body to the pin with the black/white wire and see what happens, it should have less power... though if you dont get a surge on gear change with switch unplugged then it can be some ECU misbehaviour too

Clutch switch circuit.jpg
 
sierrafery said:
Then there's a problem on that circuit, try to hook a wire from body to the pin with the black/white wire and see what happens, it should have less power... though if you dont get a surge on gear change with switch unplugged then it can be some ECU misbehaviour too

View attachment 251747
Click to expand...

Sorry for the dumb question, but where exactly should i get the 12V?
Second dumb question, from what source should come the 12V? pin35 or pin34 from ECM. I measure pin 35 and i got 0V..
 
With the plug connected to the ECU? I'll measure tomorrow on mine and let you know cos the description doesnt match the diagram... is that the original ECU on your vehicle?
 
sierrafery said:
With the plug connected to the ECU? I'll measure tomorrow on mine and let you know cos the description doesnt match the diagram... is that the original ECU on your vehicle?
Click to expand...
The plugs were disconnected from ECU..
I dont know if the ECU is original since i bought the car 3 years ago. i don't have access to vehicle history.
Clutch sensor is connected to its plug.
I cant read the partnumber of the ECU since the numbers are gone... just can realize its a MSBxxxxx
 
Ok, it's normal to not find any voltage in the disconnected black plug cos the ECU should deliver that voltage, use a needle and measure on pin 35 with ECU fully connected, it should be voltage there and drop to 0 with clutch depressed
 
sierrafery said:
Ok, it's normal to not find any voltage in the disconnected black plug cos the ECU should deliver that voltage, use a needle and measure on pin 35 with ECU fully connected, it should be voltage there and drop to 0 with clutch depressed
Click to expand...
Ok, understood. I can try only tomorrow afternoon.
So for my understanding, this 12V from pin 35 then goes to the plug from clutch sensor? and if pedal pressed goes to BCU? this means that if ECU are with plugs connected in some point i should have 12V on sensor plug?
 
That's why i said that it's a mess with that circuit cos i can't be sure as the description is not correct, on manuals the BCU is not involved in this but it should be 12V on the BW wire in the switch's plug, i'll measure tomorrow on mine and tell you
 
sierrafery said:
.... it should be 12V on the BW wire in the switch's plug, i'll measure tomorrow on mine and tell you
Click to expand...
I can confirm now there is 14V in the switch's disconnected plug pin 1 with engine running... a hint, it's hard to work with the retaining clip on the plug from behind as it was from factory, simply push it on through the slots from the front cos it clicks in place that way too and it's much easyear to handle
 
Last edited:
sierrafery said:
I can confirm now there is 14V in the switch's disconnected plug pin 1 with engine running
Click to expand...
Hi,
@sierrafery thanks for the update. You mean that this 14V are in the plug of the clutch switch right?
Mine have nothing...
Now, need to understand from where comes this 14V. I don't know if this is a broken wire or any function deactivated somewhere...
Any clue from you?
Thanks for all support that you are giving!!!
 
Curiously, when I fitted mine it didn't work. Diagnostics said it was fine. Well, I thought. I have lived without it for years, so I just shrugged and put it on the back burner for maybe investigating, someday....
And then one day, the rear wiper stopped working - and cruise control started working. I have very carefully not investigated this. So, not really helpful to anyone, least of all the OP, .....but I have working CC and no rear wipe. Happy days!
:D
 
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