Intemittent brake lights

Post by **bigginger** » Sun Oct 23, 2005 1:33 pm

Lou's car Bert started only showing brake lights when she felt like it the day of the web site rally. Cam and I thought we'd sorted the problem, but it has started again. Lou's away for the half term break with the rest of her family, leaving her eldest to try and sort the problem out if he wants to drive the car. I passed on to him what seemed to solve it last time (cleaning up the contacts on the brake light switch), and he's tried that again, but with no luck. Having only ever owned LCVs, the rear of a saloon is a mystery to me, so I'm finding offering more advice a bit tricky. Any thoughts/ideas/advice? It'd be best to make what you're saying pretty clear - I'd guess it's going to be an earth, but neither he nor I know exactly where the earth is...

Post by **Packedup** » Sun Oct 23, 2005 1:59 pm

If you've got a multimeter and a spare pair of hands it shouldn't take too long to trace. I don't know saloons either (although I've probably fitted a saloon loom to the pickup, still it seems to fit so far) but it can't be that tricky. Simply check is power to the switch (it is activated by pressure in the brake lines, isn't it?), then with someone pressing the pedal check power's coming out the other side of the switch. If that's all good then find the wire at the back (it's all bullet connectors IIRC, one wire runs down then splits to feed each light), diconnect it and with someone pressing the pedal make sure there's power at the end of it. If so, then put it back in the bullet, and check there's power coming out the bullet to the clusters.

If both light clusters are getting power for the brake lights, then it has to be bulbs, connections in the holders, or a poor earth (do the tail and indicator lights work?).

If you don't have any sort of meter then find anything 12v with wires hooked up to it - I've used anything from a bulb to an old PC fan.

I know some people might suggest working from the back forwards, I just think it's easier to go front to back

Post by **Matt** » Sun Oct 23, 2005 2:03 pm

there is a bullett connector in the boot floor, when i have a lack of brake lights its because something has moved around in there and pulled the connector off....

Post by **bigginger** » Sun Oct 23, 2005 2:07 pm

I should've said - He's in Kingston (upon Thames) and I'm in Somerset, so it's a question of whether he has a multi meter - I do, but the wires won't reach! Bullet connectors in the boot sound very plausible - I remember one of them (passenger side, Alex!) did feel a bit loose.

Post by **Packedup** » Sun Oct 23, 2005 2:23 pm

Still worth checking power is going in and back out the switch before head scratching with bullet connectors I reckon

Although it most likely is a bullet at the rear (or the switch, I've had no brake lights on an old Mini once, and didn't know it had a switch in the brake line instead of on the pedal!) it can be very puzzling to spend hours finding them all, cleaning them, refitting them only to find there's still nothing happening! Hence start where there's power and work back till there isn't - At worst it adds 10 minutes, at best it saves hours and headaches in my experience

Post by **bigginger** » Sun Oct 23, 2005 2:47 pm

I agree - it'd be a lot easier if I was actually there. I'm a bit miffed that the 'cleaning the connectors at the top of the brake light switch' didn't work this time - gave me hours of headaches once upon a time

Post by **Cam** » Sun Oct 23, 2005 5:09 pm

BigG,

There are 4 bullet connectors per side in the saloon boot, but one of them goes to an eyelet that is bolted to the bumper bar via a wing bolt. If this has come undone or is rusty then that could be causing a bad earth.

The eyelet bolts:

I did not like the 'time delay' that Bert experienced with the lamps. Also, they did not come on at partial brightness (likely with a bad earth or poor supply). This is why I thought it was the pressure switch as the lights came on (full brightness) after about 5-10 seconds of holding your (well Lou's) foot on the pedal. I think perhaps you disturbed the switch when you cleaned the contacts?

You could try just connecting the two wires that go to the switch together and if it works all the time and doesn't through the switch then the switch might be duff. I personally think it's the switch, especially in view of the time delay and then full brightness.

Post by **bigginger** » Sun Oct 23, 2005 5:12 pm

That's a bore - but they do, all to frequently, go wrong. I'll pass this on in case Alex hasn't checked the board. Cheers...

Post by **Stig** » Mon Oct 24, 2005 12:24 pm

I've recently learned that if you swap the old switch for the new one quickly then you can get away without bleeding the brakes, but it you leave it without a switch for a couple of minutes then the brakes definitely need bleeding afterwards. Handy hint.

Post by **Matt** » Mon Oct 24, 2005 12:41 pm

and push slowly down on the pedal, slowly forcing the fluid out, and just top up afterwards

Post by **ColinP** » Fri Oct 28, 2005 8:34 am

and with the front of the car raised on axle stands....

I also found that I had to take the multi-way connector out, 'cos I had to clamp the body in a Workmate to get sufficient torque to undo the switch

.

So I had to bleed the brakes as well...
Used the new Ezeebleed system - and it worked well (until I sheared the bleed nipples on the front brake)

All the best,

Colin

Post by **bigginger** » Fri Oct 28, 2005 11:20 am

Alex didn't get to the bottom of it

, so his Granddsd (electrical engineer) is going to have a go this weekend. Good luck!

Post by **Lou** » Fri Oct 28, 2005 1:07 pm

Thanks for all your help while I was away guys; will pass all this on to Dad at the weekend