Dashboard lights - help :)

[frog]

Hello everyone,

A little question to ask all you nice folk as I'm stump'd with this one..

I went to start my S1 and noticed that all the dashboard lights were on (about half brightness) before I put the key in the ignition or disabled the alarm...eeeekkk. I disabled the alam with my bliper, put the key in - turned to first position and all looked OK, started the engine first time as normal and all dashboard lights went out as normal - strange. Switched off and after about 5sec all the dashboard lights came on again(about half brightness)....mmmm

So I reapeated this just to make sure I wasn't imagining things - and it was the same again. Took the car for a blast, got home, removed keys -same thing happend. Disconnected battery for about 30min and it's still the same. The car runs/starts and does everything as normal except when the ignition is shut off (or leaving the keys in at position 0 or 1) then all the dashboard cluster lights are on(about half brightness). Sometimes all the lights are dimley lit other times its only some of them- but always the SeatBelt & Oil lights. I've tried all the electrics (wipers,lights,etc) everything is OK, but nothing will eliminate the dim dashboard lights appart from starting the car. There is no problem with the lights when the car is running !!

Any ideas about how to solve this little gremlin would be much appreciated.

thanks
Frog

[Rich H]

Could be something dicky in the side and headlamp switches, are they lit up too?

[robin]

The seatbelt and oil pressure lamps are earth switched meaning that the +ve side is fed from the ignition and the -ve side goes through a switch to earth. When you aren't wearing your seatbelt and when the engine is stopped, both of these switches will be ON.

The lamps are glowing dimly because something is back-feeding the ignition.

First port of call is to remove the MFRU and see if the lights stop glowing.

If they don't carefully remove each fuse in turn, checking whether or not the lights go out. Be careful to replace each fuse in the slot it came from before disconnecting the next fuse. When you find the fuse that stops it, let us know which one it is and then the wiring diagram will help to isolate the fault.

Cheers,
Robin

[dirkpitt]

hi frog......

off subject ...but i noticed your avatar has a red eyed tree frog....are you a owner?...as i have three of the little critters...two male and one female

[frog]

Thanks for the reply. I found the MKRU and removed it after disconnecting the battery. It all looks OK, connected the battery and the lights went out and everything appeared normal. I then reconnected the MKRU, connected the battery and everything looked fine. Started the car, took for a blast and all is normal -fingers crossed that is it fixed.

Thanks for all you help- much appreciated.


Sorry but I dont have any frogs or reptiles-wish I did as they look like fun

[robin]

I suspect you've had water ingress into the MFRU and it's probably time to look at sourcing a replacement. Moving the MFRU shouldn't have "cured" your fault ...

[frog]

Hi Guys,
the gremilns returned to my car again. Robin - your analysis/diagnostics is correct.... about the MFRU not curing my problem

I done the above of removing the MFRU and tried the ignition, however all the dashboard lights appear dim when the ignition is off (the following are not lit: Battery, indicator, headlights. Alarm light flashes as normal). When I turn the ignition to position 1 or 11 then all lights go out. Therefore the MFRU is not to blame. I then went through the fuse box and the second 7.5A fuse solves the problem- however the car won't start with it removed. I have the S1 CD manual and using my limited logic I think its the #8 fuse "Stop lamps & Battery services " fuse. I've done the usual of disconnecting the battery etc, however the dash lights are dim when ignition in position 0 or removed. Other than that the car runs perectly. From the wiring diagrams I see that Fuse 8 is on the Instruments diagram SHEET 10, and the lights that are slighly illumated appear to be B1, B2, B3, B4, B5 and the dash B9?. And now I'm stuck to try and solve this any further -has anyone got any help or suggestions...

thanks Frog.

[robin]

Frog, I'll check out wiring diagram tomorrow if nobody else has worked it out before then.

Cheers,
Robin

[Mikie711]

Fuse 8 feeds quite lot of stuff looking at the wiring diagram. OBD2 socket (pin16), the alarm warning in the instrument pack, horn relay, stop lamp switch. My thought would be dodgy earth connection but see what Robin comes up with coz he is the dude when it comes to all things electric if fact all things everything

[robin]

It's a bit of a mystery, actually.

Are your brake lights dimly lit too?

Do your brake lights work when the ignition is off (assuming you've refitted the 7.5A fuse).

Those circuits have independent earthing points and independent switches. The lamps in the dash are LEDs (supposedly) which means they will only light when current is passed through them in the normal direction (unlike an old school bulb that will light both ways - it's that bidirectional capability that causes the common "disco" lights at the back of old cars when the indicator blinking causes all the lights to blink dimly).

So I cannot see where a common drain path is for the current that is lighting these lights dimly, unless it's the stack itself.

Not much use I'm afraid ...

Cheers,
Robin

[frog]

Hi,

thanks for all the help. Sorry for not posting ealier as I've been on holiday for a good few weeks and also been monitoring the Elise. All appears fine now over the last 2/3weeks - done nothing to the car appart from drive it a few times - strange. I did speak to a mechanic and he said that this maybe a faulty earth and if it happens again to connect an earth to the speedo and onto the chassis/dashboard. Thankfully I've not had to try this.

thanks again for all your help
Frog.