Bad earth?

[hicksy]

Evening all,

 

As my SUYM thread ive recently bought a mk6 RS2k with a duff engine.

 

Ive got the new engine in and its running like a dream. The problem im having is that the battery is now draining over night The light on the heated rear screen button stays on even when the key is taken out (ive taken the fuse out and it still does it) Ive checked and double checked the connections under the bonnet and i cant see a problem. Ive cleaned up the earth between the gearbox and the chassis because that was scabby but that still hasnt sorted it

 

Any ideas? Im at a bit of a loss

 

CheeRS Tom

[shawdreamer]

Evening all,

 

As my SUYM thread ive recently bought a mk6 RS2k with a duff engine.

 

Ive got the new engine in and its running like a dream. The problem im having is that the battery is now draining over night The light on the heated rear screen button stays on even when the key is taken out (ive taken the fuse out and it still does it) Ive checked and double checked the connections under the bonnet and i cant see a problem. Ive cleaned up the earth between the gearbox and the chassis because that was scabby but that still hasnt sorted it

 

Any ideas? Im at a bit of a loss

 

CheeRS Tom

 

like you guessed bad earth (hinge, next to rear lights or copper contact points), failing that it'll be the wiring were it passes from the bootlid, through the rubber connecting tube and into the cab, had the latter issue a while back on my Si..... I ended up having to pull a new loom into the bootlid (not a fun job)

[hicksy]

Evening all,

 

As my SUYM thread ive recently bought a mk6 RS2k with a duff engine.

 

Ive got the new engine in and its running like a dream. The problem im having is that the battery is now draining over night The light on the heated rear screen button stays on even when the key is taken out (ive taken the fuse out and it still does it) Ive checked and double checked the connections under the bonnet and i cant see a problem. Ive cleaned up the earth between the gearbox and the chassis because that was scabby but that still hasnt sorted it

 

Any ideas? Im at a bit of a loss

 

CheeRS Tom

 

like you guessed bad earth (hinge, next to rear lights or copper contact points), failing that it'll be the wiring were it passes from the bootlid, through the rubber connecting tube and into the cab, had the latter issue a while back on my Si..... I ended up having to pull a new loom into the bootlid (not a fun job)

 

 

Thanks for the reply

 

Ive cleaned up the copper contacts on the boot and the car, so ill have a looksie at where the wires come through into the boot Fingers crossed that sorts it

[Ahmotorsport]

Did it do this before you changed engines?

[hicksy]

Did it do this before you changed engines?

 

I dont really know, as soon as i got it i parked it up and pulled the engine out

[shawdreamer]

Evening all,

 

As my SUYM thread ive recently bought a mk6 RS2k with a duff engine.

 

Ive got the new engine in and its running like a dream. The problem im having is that the battery is now draining over night The light on the heated rear screen button stays on even when the key is taken out (ive taken the fuse out and it still does it) Ive checked and double checked the connections under the bonnet and i cant see a problem. Ive cleaned up the earth between the gearbox and the chassis because that was scabby but that still hasnt sorted it

 

Any ideas? Im at a bit of a loss

 

CheeRS Tom

 

like you guessed bad earth (hinge, next to rear lights or copper contact points), failing that it'll be the wiring were it passes from the bootlid, through the rubber connecting tube and into the cab, had the latter issue a while back on my Si..... I ended up having to pull a new loom into the bootlid (not a fun job)

 

 

Thanks for the reply

 

Ive cleaned up the copper contacts on the boot and the car, so ill have a looksie at where the wires come through into the boot Fingers crossed that sorts it

 

were the wires are concerned, look for any signs the insulation has been stressed (slightly lighter colour the the rest of the wire coating) or shows any indication that its suffered a bend or kink in or around the grommits.

 

after exhausting all avenues with the exact same problem I resorted to checking the wiring inch by inch and found that just were the wire passes out the cab and into the tube grommit that connects to the bootlid the wires has spiralled round each other and two had become so stressed whenever the boot was opened and closed that they'd kinked and eventually rubbed through their insulation clean through which caused a earth arc.

 

wasn't just the demister though in my case, it caused alsorts of weird malfunctions, along with the demister light coming on like yours it'd sometimes flash faintly with the hazards, go off when rear fogs went on and even flat out refuse to turn the demister on wether it was lit or not..... the faults seemed to vary each time the boot lid was opened and closed, was like a game of Ford electrical roulette.

[demented]

There's a possibility that a relay is remaining active/closed when the ignition is switched off, so technically the relay is powered, this will discharge a car battery overnight.

 

Check for any relays that feel hot with ignition off and when vehicle has been unused overnight.

 

Such a problem can occur if a relay has failed due to wear n tear and is stuck in the closed position or maybe the wrong relay has been fitted.

 

There is also the possibility the correct relay has been used but fitted incorrectly.

 

Also, it's  worth ensuring that the boot light is actually extinguishing when tailgate is closed.

 

If you suspect the issue is due to the heated rear screen, remove the rear screen relay and see if same issue occurs or unplug and tape up connector at the terminals on the rear screen.

 

Rather than having a bad earth, you more than likely have a short circuit. 

 

A bad earth will normally prevent a car from starting, fail to charge the battery or cause an electrical component to interfere with another and or, not operating as expected, I've never known a bad earth to discharge a battery.

 

If its not an issue with a relay or connector being plugged into the wrong socket, then a wire is causing an electrical component to operate when it should not.

 

It's my believe that all electrical components and relays on a vehicle are connected to a permanent earth and are operated by a switch, whether the ignition switch or an individual switch,  it's a switched live (positive) that activates the component.

 

It's also my believe that the majority of components and relays are inactive when ignition is off. 

 

There are exception, such as tailgate release, interior light delay etc, however, although these relay operated with igntion off, they remain inactive until operaterated via a switch.

 

So, to narrow this down, an electrical component is being provided with a live when ignition is off and operating as expected when it shouldn't, (sorry if thats stating the obvious) otherwise, wires would melt, overheat and hopefully blow a fuse.

 

If wire insulation had rubbed through, exposing a live wire which makes a permanent contact with the bodywork/Earth, this would most certainly blow a fuse, otherwise it would overheat, melt and maybe ignite.

 

However, a live wire intermittently making a Earth can do so many times without overheating, melting or blowing a fuse and such a occurrence will NOT cause a battery to discharge overnight.

[hicksy]

There's a possibility that a relay is remaining active/closed when the ignition is switched off, so technically the relay is powered, this will discharge a car battery overnight.

 

Check for any relays that feel hot with ignition off and when vehicle has been unused overnight.

 

Such a problem can occur if a relay has failed due to wear n tear and is stuck in the closed position or maybe the wrong relay has been fitted.

 

There is also the possibility the correct relay has been used but fitted incorrectly.

 

Also, it's  worth ensuring that the boot light is actually extinguishing when tailgate is closed.

 

If you suspect the issue is due to the heated rear screen, remove the rear screen relay and see if same issue occurs or unplug and tape up connector at the terminals on the rear screen.

 

Rather than having a bad earth, you more than likely have a short circuit. 

 

A bad earth will normally prevent a car from starting, fail to charge the battery or cause an electrical component to interfere with another and or, not operating as expected, I've never known a bad earth to discharge a battery.

 

If its not an issue with a relay or connector being plugged into the wrong socket, then a wire is causing an electrical component to operate when it should not.

 

It's my believe that all electrical components and relays on a vehicle are connected to a permanent earth and are operated by a switch, whether the ignition switch or an individual switch,  it's a switched live (positive) that activates the component.

 

It's also my believe that the majority of components and relays are inactive when ignition is off. 

 

There are exception, such as tailgate release, interior light delay etc, however, although these relay operated with igntion off, they remain inactive until operaterated via a switch.

 

So, to narrow this down, an electrical component is being provided with a live when ignition is off and operating as expected when it shouldn't, (sorry if thats stating the obvious) otherwise, wires would melt, overheat and hopefully blow a fuse.

 

If wire insulation had rubbed through, exposing a live wire which makes a permanent contact with the bodywork/Earth, this would most certainly blow a fuse, otherwise it would overheat, melt and maybe ignite.

 

However, a live wire intermittently making a Earth can do so many times without overheating, melting or blowing a fuse and such a occurrence will NOT cause a battery to discharge overnight.

 

Thank you for taking your time to write that up for me, thats much appreciated

 

Ive had another look at the car today and ive tried taking the relay and the fuse for the rear screen out. The light on the heated screen button dims but doesnt go out completly :S

 

I also took every fuse out one at a time to see if that made the light go out but that didnt work either The only one that effected the light was taking the fuse out for the rear screen (but it still didnt extinguish the light)

 

However when i was looking at the fusebox i noticed water ontop of it, it seems that there is a leak and water is getting into the fusebox Im going to take the fusebox off later to dry it out and see what condition it is inside.

[Rockerrob666]

There's a possibility that a relay is remaining active/closed when the ignition is switched off, so technically the relay is powered, this will discharge a car battery overnight.

 

Check for any relays that feel hot with ignition off and when vehicle has been unused overnight.

 

Such a problem can occur if a relay has failed due to wear n tear and is stuck in the closed position or maybe the wrong relay has been fitted.

 

There is also the possibility the correct relay has been used but fitted incorrectly.

 

Also, it's  worth ensuring that the boot light is actually extinguishing when tailgate is closed.

 

If you suspect the issue is due to the heated rear screen, remove the rear screen relay and see if same issue occurs or unplug and tape up connector at the terminals on the rear screen.

 

Rather than having a bad earth, you more than likely have a short circuit. 

 

A bad earth will normally prevent a car from starting, fail to charge the battery or cause an electrical component to interfere with another and or, not operating as expected, I've never known a bad earth to discharge a battery.

 

If its not an issue with a relay or connector being plugged into the wrong socket, then a wire is causing an electrical component to operate when it should not.

 

It's my believe that all electrical components and relays on a vehicle are connected to a permanent earth and are operated by a switch, whether the ignition switch or an individual switch,  it's a switched live (positive) that activates the component.

 

It's also my believe that the majority of components and relays are inactive when ignition is off. 

 

There are exception, such as tailgate release, interior light delay etc, however, although these relay operated with igntion off, they remain inactive until operaterated via a switch.

 

So, to narrow this down, an electrical component is being provided with a live when ignition is off and operating as expected when it shouldn't, (sorry if thats stating the obvious) otherwise, wires would melt, overheat and hopefully blow a fuse.

 

If wire insulation had rubbed through, exposing a live wire which makes a permanent contact with the bodywork/Earth, this would most certainly blow a fuse, otherwise it would overheat, melt and maybe ignite.

 

However, a live wire intermittently making a Earth can do so many times without overheating, melting or blowing a fuse and such a occurrence will NOT cause a battery to discharge overnight.

 

Thank you for taking your time to write that up for me, thats much appreciated

 

Ive had another look at the car today and ive tried taking the relay and the fuse for the rear screen out. The light on the heated screen button dims but doesnt go out completly :S

 

I also took every fuse out one at a time to see if that made the light go out but that didnt work either The only one that effected the light was taking the fuse out for the rear screen (but it still didnt extinguish the light)

 

However when i was looking at the fusebox i noticed water ontop of it, it seems that there is a leak and water is getting into the fusebox Im going to take the fusebox off later to dry it out and see what condition it is inside.

 

 

that will probably be your problem then, the fact that you can remove all of the fuses and a current is still flowing to the led will show that you have a short or a cross wire somewhere where current is passing from a point it shouldn't be coming from to the rear window heater (and god knows what else) depends how bad the water in the fusebox is, the water will be allowing the current to by-pass all of the fuses / relays and keep the current flowing to the heater.

 

I think you'll need to sort where the water is coming from regardless of whether it's actually having an effect at the mo, water on a fusebox = not good! especially if, when you accelerate, it pours off the top onto your foot with a current passing through it!! get the leak sorted and hopefully that will also sort the power drain!