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Discussion Starter · #1 ·
2004 Disco. 97K miles.
Started with a fast blinking left signal light. Pull to the side and noticed the left rear signal light is not on. Tab the cover a few times and its working again. Didn't last very long and the fast blinking came back on. Went and got two pairs new bulbs including the two side brake light bulbs per spec. Replaced them all with new bulbs and thought that should be it.
Next morning, noticed I have no brake lights when looked at the widow reflections in rear while in reverse, not even the one in the top center which I didn't touch all these time. Checked all lights are working including revers lights but just no brake lights at all.
Went online research and read the forums, check the brake switch and fuse #25 (15A) under the steering wheel are all seems fine. I even remove the brake switch off the arm of the brake paddle, disconnected wire from the switch and put it back on, test the plunger and all seems to be in good condition!
Question: No problem shifting gears when the engine is on. Can't shift out of Park when the engine is off. How can I tell if the brake switch is the problem?
This rig is not my daily driver. Battery is about 5 years old and I do have a cheap brand "battery float charger" when parked. Could that be a problem? I have no issues starting up the rig at all.
Look forward to your responses. :frown
 

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... How can I tell if the brake switch is the problem?
...
Unplug it, take a piece of wire and with ignition on bridge pin 1(green/orange wire) with pin 3(green/purple) in the plug.... if you'll get brake lights this way the switch is gone...the switch is quite suspect anyway cos it is involved in the selector interlock action too, this interlock stops it from being removed from P with ignition off
Selector lever interlock (where fitted)
The interlock solenoid on the selector lever is de-energised unless the foot brake is applied while the ignition is on.
While de-energised, the interlock solenoid allows the selector lever to move through the range unless P is selected.
On entering the P position, the interlock solenoid engages a latch which locks the selector lever. When the ignition is
on and the foot brake is applied, the BCU energises the interlock solenoid, which disengages the latch and allows the
selector lever to be moved out of P.
 
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Discussion Starter · #4 ·
Unplugged, bridged ping 1 & 3, with ignition at on position, no brake lights. i.e. it's not the brake switch then?
What else could it be?
I do hear clicking sound when bridging the two pins.....
 

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I do hear clicking sound when bridging the two pins.....
Where's sound?

Do you have a meter to check for power and ground at the switch plug? If not invest a few bucks in one. Should be 12v power on one terminal and some amount of resistance to gnd.
......
 

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The clicking sound means that there is feed at the switch cos that's the sound of the "hill descent relay" part of the interior fusebox which is used for the ABS system...it seems that there is a problem on the circuit between the brake pedal switch and the header where the feed from the swich splits

a common failure point for other connected systems too is corrosion/bad contact in C0484(attached) check there on pin 9(green/purple wire) if you get feed with pedal depressed cos from there it goes to the split point
 

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Discussion Starter · #7 ·
I can only hope for 'bad contact' in C0484 because corrosion is our of the question (I think), all looks clean like new around that area. Just unplug and do visual inspection?

To number9, I do have a multi-meter. Can you tell me how do I go about testing the grounding on the brake switch?
 

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At pin 9 of C0484 you have to check for live with brake pedal depressed both sides of the connector with it plugged cos the feed must get there from the switch, there is no ground at the switch it switches the live to the circuit but as long you hear a clicking sound when you press the switch the problem is not there IMO...dont unplug that connnector with ignition on

anyway, check for voltage on the green/purple wire at the switch too cos from there it must get to that pin 9 coming from the closed switch
 

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Discussion Starter · #9 ·
I will verify corrosion/bad contact in C0484 specially for pin #9 (while the key is OFF position). If that looks OK, I will plug it back in, turn the ignition to ON position and press the brake paddle, if I hear clicking sound. That means my brake switch is good?
That's what you want me to check, right?

As mentioned, I do have a multi meter but don't know how to use it. :-(
How do I go about check for voltage on the green/purple wire at the switch? What do I do and what am I suppose to look for on the multi meter? Electrical is my weakest link. :p
 

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You should set the multimeter on 20V DC if it has this scale if not on the lowest above 12V, put negative probe to a metalic part of the body and positive where you want to measure, if you can't reach the pin from behind in the connected plug insert a thin needle there to be sure it touches the contact and measure on that....first of all make sure there is voltage on the green/orange wire at the pedal switch
 

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Download these:
1. https://www.dropbox.com/s/xltgqg0u1...S MY03 - Electrical Circuit Diagrams.pdf?dl=0
2. https://www.dropbox.com/s/5hp0xo1y5a79621/Discovery 2 NAS MY99 to MY03 - Electrical Library.pdf?dl=0

find somebody who knows basic electrics, no special need for auto electrician just somebody who can read a diagram and use a multimeter, in the diagrams file go to Exterior lamps - Brake and reverse lights ... there you can see the path from fuse F25 through the switch untill the lights, the connectors are numbered... in the Electrical library - connector views you can find by it's number the involved connector's picture and pin disposals(like the one i attached earlier), check voltage starting from the switch on each connector as they are on the circuit to find where the feed is lost....simple as that :wink
 

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Discussion Starter · #13 ·
I had a hard time to disconnect the C0484 plug. Do I press down the middle tab down and pull the plug apart? It's stiff and I didn't want to force it and brake something....
While I had the brake switch off the brake paddle arm, with ignition at on position. I push the spring loaded brake switch, I can hear the clicking sound but no brake lights at all. Doesn't that mean the wiring is good and the switch is functioning?
 

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If you hear the click from the fusebox or glovebox area then yes the switch is good and the wiring untill the first header joint is good but the C0484 is after that joint and from there the feed goes to the header where it splits for the lamps... iirc those type of connectors like 0484 have some locking clips on the sides but i've never unpluged that one myself, measure for feed on that green/orange wire without disconnecting it as i previously told you by using a needle if you can't reach the pin with the multimeter's probe
 

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Discussion Starter · #15 ·
The clicking sound is from two places. One from under the gear selector and one from under the steering wheel area.
Also, the orange and green wire at the brake switch has 11.67 and about the same reading at C0484 pin #9 when I tested with my multi-meter, setting at DCV 20.
Bad brake switch?
 

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As long as you have feed at C0484 and those clicks are the evidence that the switch is good cos the feed gets to the relay, BCU and to 0484 so you have to go further on the path to header C0295, also green/orange wire(see the connector view in that electrical library link i gave you).... though are you sure that the bulbs are not all shot cos it is possible, they dont share the same earth only the same feed that's why an earth issue is not very obvious
 

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Discussion Starter · #17 ·
Will go back and check the bulbs again. Anything in the left rear towing elements I should check while I have the light cover off?
Also, for $28 I bought a new brake switch! Hope I can clear this up by the weekend. Thank you very much for being so patience with me! Wish I can buy you a beer or two....
 

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I'm glad it's sorted though i'm wondering how did you get feed at C0484 with a bad switch or why didnt you have lights when you bridged pins 1-3 in the switch's plug cos that's completely odd
 
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