75ZT Community

Been getting the 'light out' icon on the dash on and off for a couple of weeks now. Strange one as the light icon will appear and minutes latter go out again thought it may be a dodgy bulb.

NOPE!

Wiring loom plug contacts are corroded slightly, so out came the WD40 (will leave to dry over night me thinks).

HOWEVER!
I manage to snap off the little spade arm thingy that holds the rear light bulb unit in anyone even done that before (must be very brittle).

So now need a new light unit all becasue of one little snapped bit of plastic I think I may do a repair mod which should make it stronger........

not heard of that one before !

takestock wrote:not heard of that one before !

Really! thats not good then......

Dave! the story gets more puzzling.........

Thought I do a quick repair regarding the broken plastic push arm thingy, then to find the problem with the light-out bulb coming on is still present.

When I switch on the normal headlights the rear brake lights come on for 2-3 seconds and then go out allowing for the normal rear lights then to come on. (the light-out icon comes on even though there is no bulb blown).

It does not do this every time but at least 5 times out of 10 the problem occurs.

When wiggling the wire loom plug that plugs into the black light cluster casing this then either turns the brake lights off or back on (also activates the light-out icon on the dash).
Does this on both sides when wiggling each plug, something is very wrong and I cant find what it is.................. would really appreciate some help fellas......
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If a rear light bulb is blown (or if the car thinks the bulb is gone) then it'll cleverly illuminate the corresponding brake light bulb (but at a slightly reduced intensity) to compensate.

If you've got a dodgy connection or bulb then this will explain why the problem is intermittent.

aaaaaaaaarrrrrhhh! Simon YES! I found that when I would take out the normal 5W rear light bulb it would automatically illuminate the brake light bulb dimly (so that explains that one).

I have spent all morning on this now and I cant find what the fault is.

The symptoms are.......
1. Bulb fault icon is on (even though all bulbs are working).

2. Sometimes the bulb fault icon goes out when I apply the brake pedal.

3. Turn headlights on showing rear lights, sometimes the left brake light also lights up dim (this then shows the bulb fault icon on dash).

4. Turn headlights on showing rear lights, sometimes the left light is out and the left brake light is on instead (dim). This then shows the bulb fault icon on dash.

5. These symptoms happen to the left and right side, but not at the same time.

So I do have a variant combination of the light set up, I can sometimes have one or two rear lights on with one brake light on even though I am not braking.

Now! if I think back I can remember months ago that the bulb fault light icon did come on a few times and I noticed when I applied the brake pedal the light would go out, so I though nothing of it. But it seems that the problem has got worst and somehow must be connected to the brake system (I don't know).

It must be an electrical problem and allowing for the bulb fault light to trigger and allow for a brake light to illuminate dimly when headlights are turn on.

Who is the electrical wizz-kid around here then (Simon) help will be really appreciated. I dont want to get rid of the Rover just becasue of a light fault, and if I take it into a garage they will charge me silly money to rectify.

OH! Nothing has been replaced or worked on recently that might cause the problem, she has been untouched since her last MOT.

Its not ECU (Engine Control Unit) related is it? or some relay? Can it be as simply as a faulty bulb.

Another update!

Now the battery has gone flat where I have been having the lights on etc it is the same battery that went flat all of a sudden last year.

May this be the electrical problem if the battery appears to be shot (faulty) knackered.

Dodgy battery can produce some very odd effects on our cars.

Mick wrote:Dodgy battery can produce some very odd effects on our cars.

Hi Mick! I've just put on a spare battery and still the bulb fault is present, ok the battery is 62amp compared to 75amp but the car starts perfect.

At least the GREEN glow is apparent on the battery window.....

So I am still no further with what is causing the trouble........

Don't have hiline Sat Nav do you?
These can drain battery when they don't shut down properly.

Dirty contacts on the connectors, bulb holders, or on the earth could all cause the problem. WD40 is not a cleaner (its a moisture remover) so don't rely on it. A fiberglass brush is always a good bet, with proper contact cleaner. Also remember the metal outer of the bulb us a contact so check this too.

Finally, worth a double check theres no water getting into your light switch module. Very unlikely, but possible.

JohnDotCom wrote:Don't have hiline Sat Nav do you?
These can drain battery when they don't shut down properly.

Oh! I wish..............

Duncan wrote:Dirty contacts on the connectors, bulb holders, or on the earth could all cause the problem. WD40 is not a cleaner (its a moisture remover) so don't rely on it. A fiberglass brush is always a good bet, with proper contact cleaner. Also remember the metal outer of the bulb us a contact so check this too.

Finally, worth a double check theres no water getting into your light switch module. Very unlikely, but possible.

Well I have checked everything that I know of and still she has the same problem, I have even changed all rear bulbs for new ones which was pointless.

Its like Russian roulette one minute you turn ignition on and all ok, but the next time the fault bulb icon appears and I have one brake light on and just one normal rear light on. I have just been out again to check and I switched on lights and just both brake lights came on but no normal rear lights. I gave both rear light clusters a tap and both brake lights went out and both normal rear lights then came on....... go figure.

I have checked all connections and all are clean, bulbs are tight and all work. The original battery is a 75amp and is on charge, the battery on at moment is a 62amp and is good. I see from the owners manual the 1.8's can have 61amp/hr and all other models 75amp/hr.

So I wounder if its a battery problem, but nothing else is effected.

Any ideas fellas.

Dallas wrote:I gave both rear light clusters a tap and both brake lights went out and both normal rear lights then came on....... go figure.

This indicates some faulty connection within the holder of the rear lamps or nearby. Otherwise the tap wouldn't have any effect.

Jürgen wrote:

Dallas wrote:I gave both rear light clusters a tap and both brake lights went out and both normal rear lights then came on....... go figure.

This indicates some faulty connection within the holder of the rear lamps or nearby. Otherwise the tap wouldn't have any effect.

I agree. Tapping the lamps won't affect the battery.

I have come across on other cars, the metal tracks that go from connector to bulb, coming unclipped. This means they aren't contacting the connector or bulb holder properly.

Definiteyl sounds the bulb end and nothing to do with the battery

YEP! I see what you mean fellas

This is what happened earlier today...........
1. Main original battery is still on charge (tried earlier and still flat).
2. Fitted 1.8 62amp battery but did not tighten the positive/minus terminals.
3. Switched lights on and both rear brake lights came on instead.
4. Fault bulb icon came on.
5. Tapped both rear light units and both brake-lights went out and normal lights then came on.

6. I repeated the same process but this time I tightened the battery terminals which then turned the brake lights off and normal lights then came on.

So it may look as though the battery is at fault after all, what I will do is drive around a few days with the 1.8 battery on while the original battery is charging and see what happens. If still have problem then will have to see if original battery is ok or may have to buy a new one and test lights with new battery.

If still problem after that, then most probably will need two new light units.

Well it cannot be the battery as the fault is still present with either the two batteries.

It cannot be the light cluster's having poor connection etc, I have cheeked all contacts and connections and everything is ok. Would it be a relay or ECU problem, the fault is permanently there now.

I have just turned on headlights and I had no rear lights, just both rear brakelights came on dim I gave both rear lens light units a tap and both rear lights came on and both brakelights went out.

I am totally confused, what could be the problem? Trouble is! its gonna make it illegal to drive with lights acting up like this. Any help will be most appreciated.

Can someone do a quick test for me on their car please.

Turn on ignition and turn on headlights, unplug either of the rear lights plugs from the rear light cluster unit and then plug back in again (can you tell me what happens).

When I do this both rear brakelights come on first and then go out within seconds, which then brings on the normal rear lights :shrug: I'm sure this is not correct.

Can anyone check this on their cars please, will be most appreciated.

I assume that you tapped one, and that light came on, then tapped the other and it came on?

Have to say it has to be the lamps bulbs or wiring otherwise how would tapping the lamp make any difference? It is vaguely possible that the problem is not an open circuit (corroded, broken) but a short circuit (insulation worn through) but it's so unlikely to be the same fault both sides, I seriously doubt it.

Add to that, the circuits for each tail lamp are separate, and I can't see how they can affect each other.

Hi Duncan, Yes both sides do the same, either both together or separately.

I agree with you when you mention about a broken or corroded circuit, but as you say on both sides is a bit unbelievable.

Duncan can I ask a favour, would you be able to go out and check your light clusters for me by switching ignition on and turn on headlights, unplug either of the rear lights plugs from the rear light cluster unit and then plug back in again (can you tell me what happens).

When I do this both rear brakelights come on first and then go out within seconds, which then brings on the normal rear lights :shrug: I'm sure this is not correct. Sometimes the brakelights do not even go out, they just stay on dim and I have no normal rear lights.

Unfortunately the battery is low on the saloon and needs a charge. I'll try to get time this evening to try it once I have the charger on.