Brake Lights always on

Post by **fweddy** » Tue Mar 16, 2004 9:34 am

Seem to have a problem with the brake lights on Dad's car. When you start up and drive away they are off but when you first use your brake they come on and stay on. When you use the brake after this it gets a little brighter. When you turn on the lights it also gets a little brighter - I'm pretty sure its the brake filliment that is lit.

The other day Mum went to go out in it (her first time to use it to go some where rather than up the road and back forthesake of it

) it wouldn't start - battery flat as anything. Tried jumping it, but the cables were too small - then tried pushing it but it was flooded and we got tired pushing. Finally got the motorbike to tow it and she started and went fine. Dad went to town and gave it a charge and it started again after the run.

Today I went to use it again and it was pretty flat again (no start). So a quick push and we were under way. I left it running every where I went (except at the fuel station where my bro was sure it would start again - it didn't - he pushed!

).

While he was shopping I checked the brake 'sender unit' - the thing at the front of the engine bay that the wires connect to to turn the brake lights on (I think). It was very hot - as was the brake light mounts.

Is it likely that there is a link between the battery problem and the brake lights? (battery may be just plain old)
How should I approach fixing the brake lights? (When we went for the WOF - like your MOT - they happend to come on when checked, and the chap didn't notice they stayed on!

)

Post by **rayofleamington** » Tue Mar 16, 2004 9:49 am

A combination of permanent brake lights and a weak battery is not a good thing. However just trying to charge the battery on a run isn't ideal. Best to leave it at least 12 hours on a charger.

If the battery is gone it won't hold charge for very long so you might find it flat after a few days anyway. Can you get a garage to do a battery discharge test for you? (uses a big resistor to draw high current and the movement of the dial shows the state of the battery).

Post by **newagetraveller** » Tue Mar 16, 2004 10:34 am

It sounds as if the brake sender unit may be sticking in the on position when you first press the brake pedal.

Post by **lowedb** » Tue Mar 16, 2004 1:09 pm

I had the same problem when I first got the mog. The master cylinder was a bit suspect, so the pushrod had been over adjusted to stop the fluid coming out of the back. Problem was, it also stopped the brakes releasing and hence the light goingoff. The workshop manual tells you how to check clearances on the pushrod.
On the battery, it sounds like the battery or charging system rather than the brake lights. As far as I know, the brake lights on mogs only work with ignition on (please feel free to contradict me, I've not checked the circuit diagram) so they wouldn't flatten the battery when the ignition is off.

Post by **rayofleamington** » Tue Mar 16, 2004 1:59 pm

so they wouldn't flatten the battery when the ignition is off.

very true, but if the battery is flattened with ignition on, you quite often don't realise until you try to crank the engine.

Post by **Matt** » Tue Mar 16, 2004 3:41 pm

theres a bodge somewhere in my car, brake lights work with the ignition off....

Post by **Kevin** » Tue Mar 16, 2004 4:09 pm

Finally got the motorbike to tow it

bro was sure it would start again - it didn't - he pushed!

Fweddy dont you have a starting handle ? or did you just forget that you had one, not that I have ever done that more than a few times

Post by **Matt** » Tue Mar 16, 2004 4:16 pm

and it must have been a big bike.....

Post by **fweddy** » Tue Mar 16, 2004 7:35 pm

It sounds as if the brake sender unit may be sticking in the on position when you first press the brake pedal.

I thought that may be the area to check. I'll have a look there and see what I can find.

As far as I know, the brake lights on mogs only work with ignition on

Yes lowedb, you are right. Its when the car is turned off that the lights go out and get a new chance. Some time they just go out anyway.

I didn't suspect the lights being on would be flattening the battery but rather it might be some electrical short which is putting the lights on and also causing the drain when the car (and lights ) are off??

The Battery problem may not be linked but just that both seem to be happening at the same time. The car had been sittign for a number of months before we got it and it started first pop and has been good but it may just be coincidental that its gone dud now.

Fweddy dont you have a starting handle ? or did you just forget that you had one

LOL - No I got the handle out to do the job but some one fitted the number plate over the crank hole!! Easier to push/tow than remove the plate! I (no dad actually) must get that sorted - would look better cranking at the fuel station rather than pushing aye! I just use his car 'cause my ute doesn't go yet.

and it must have been a big bike.....

The motorbike is a Honda ATC farm bike, i.e. low geared 250cc

Post by **Matt** » Tue Mar 16, 2004 8:18 pm

so no, its actually quite a small bike :?

Post by **Willie** » Tue Mar 16, 2004 8:52 pm

MATT>>I seem to have advised you some time ago about an electrical
anomaly on your car?? Your stop lights are connected to the
wrong fuse. The fuse with the WHITE wires on it is only live when
the ignition is ON(all the green wires should be connected to
the other side of the same fuse). The fuse with the BROWN
wire on top is live all the time, if you have a green wire connected
to the other side of this fuse then it is WRONG.

Post by **Matt** » Tue Mar 16, 2004 9:20 pm

i know, but i havent actually been home since then

and from memory the fuse box is as you described it should be :s i need to make sure the lights are fused before i go too far.....

Post by **fweddy** » Wed Mar 17, 2004 12:57 am

so no, its actually quite a small bike :?

engine wise it is relatively - But those 3 & 4 wheel ones have a good gearing. And after all the minor is a wee car too!

Post by **Matt** » Wed Mar 17, 2004 2:48 am

in other words it was a quad bike? yes they can pull well.

Post by **fweddy** » Wed Mar 17, 2004 4:34 am

Post by **fweddy** » Tue Mar 23, 2004 8:41 pm

OK I charged the battery on an over night charge and now it starts right up every time! It seems some one had left the sterio on and flattened it!

I took it down tho the shed to fix the brake lights and they were working fine now too! They go on and off like they should. Althoug htime will prove.

How does this make sense - how come if the battery is flat the brake lights stay ON but when its charged they go OFF?? Or is this soley coincidental? I'm sure the lights were faulty before the battery was drained.

Post by **Matt** » Tue Mar 23, 2004 11:42 pm

there is probably a dodgy connection somewhere................

Post by **Kevin** » Wed Mar 24, 2004 8:55 am

there is probably a dodgy connection somewhere................

Thats helpful.........

Post by **Matt** » Wed Mar 24, 2004 11:37 am

I know, but its the only thing i can think of

Post by **MrA.Series** » Wed Mar 24, 2004 12:29 pm

How highly informative!