#1: Weird Brake Light Problem Author: Lee, Location: EnglandPosted: Sat May 28, 2011 10:56 am ---- Right, had my third brake light off yesterday to change one of the resistors because it blew. Left the brake light off overnight, so the wiring connector was exposed [didn't think to cover it up].
Re-fitted it this morning, all the brake lights worked fine.
Nipped out and pulled up in a car park, and a guy said to me "only one of your brake lights is working mate". Turned out only the drivers one was, instantly knew it was the fuse.
Changed the fuse because sure enough it had blown.
Now none of the brake lights work. Fuses are intact but I'm only getting 9.42 volts to my lights, so clearly not enough to light them up. The wires at the switch get really hot as well.
Do you think the only way forward is to re-wire the brake light system?
Cheers,
Lee
#2: Re: Weird Brake Light Problem Author: V9977, Location: Athens, GreecePosted: Sat May 28, 2011 11:00 am ---- Maybe the shunt resistor was too low value (I assume LED's are involved).
That could have damaged the brake switch and you might well be OK with
just replacing the brake switch.
#3: Re: Weird Brake Light Problem Author: V9977, Location: Athens, GreecePosted: Sat May 28, 2011 11:02 am ---- Also remember brake switch is single-pole change-over so it would make sense if
NO or NC contact is permanently closed.
What value resistor are you using?
#4: Re: Weird Brake Light Problem Author: Lee, Location: EnglandPosted: Sat May 28, 2011 11:04 am ---- Changed the resistor for the exact same value. Third brake light worked fine when testing in the house, and initially worked fine on the car.
Just puzzles me why there's only 9.42 volts coming to the lights. Surely if it fried the switch, there'd be 0 volts.
#5: Re: Weird Brake Light Problem Author: V9977, Location: Athens, GreecePosted: Sat May 28, 2011 11:06 am ---- If the resistor has failed-short that would make a nice divider with the cables going to the brake light
and causing the voltage drop even though its not enough to blow the fuse.
What Ω resistor do you use and what W rating?
Maybe the new one snuffed it. Measure it.
#6: Re: Weird Brake Light Problem Author: Lee, Location: EnglandPosted: Sat May 28, 2011 11:13 am ---- Erm... lost my reference book and threw away the package name
Resistor is light brown/sandy colour. stripes are gold - brown - grey - brown.
The guy in Maplins said it was the right one.
I disconnected the third brake light, and did a very quick rewire with a relay, but still no joy. Obviously the relay wouldn't activate as there wasn't 12volts.
Original wiring diagram goes like this ......... engine fuse box (f35) > switch > drivers fusebox (f10 & f11) > brake lights (f10 = drivers, f11 = pass & third)
#7: Re: Weird Brake Light Problem Author: V9977, Location: Athens, GreecePosted: Sat May 28, 2011 11:20 am ---- Gold-Brown-Grey-Brown = 18 Ohms but what Wattage is it?
12V accross 18Ω would be 0.7A roughly which would be at least 8 or 10W
required for the resistor and it would heat up. Could it have melted
the insulation long-term or did you make sure.
I wouldn't worry about the voltage being low as I think the brake switch has had it.
#8: Re: Weird Brake Light Problem Author: Lee, Location: EnglandPosted: Sat May 28, 2011 11:24 am ---- Wattage of what? the resistors? or the brake?
Had a feeling it could have been the switch with the wires getting mega hot.
#9: Re: Weird Brake Light Problem Author: V9977, Location: Athens, GreecePosted: Sat May 28, 2011 11:27 am ---- The Wattage rating of the resistor. It could be anything from 1/2W to 25W metal or ceramic brick type..
Did it look physicaly the same as the old one or was it smaller in size?
#10: Re: Weird Brake Light Problem Author: Lee, Location: EnglandPosted: Sat May 28, 2011 11:29 am ---- Physically the same. Took it off and shown it the guy, and also took the whole circuit board. Was exactly the same.
Found the pack, all it says is "resistors" on it And I had to buy 50, t*at
#11: Re: Weird Brake Light Problem Author: V9977, Location: Athens, GreecePosted: Sat May 28, 2011 11:33 am ---- I would start with replacing the switch making sure you have correct voltage delivered without
the 3rd light connected.
Then make sure you use a hefty resistor to handle the heat and current so you know its not
from there. You should ask for at least a 10W like this:
#12: Re: Weird Brake Light Problem Author: Lee, Location: EnglandPosted: Sat May 28, 2011 11:36 am ---- Those resistors won't fit on the circuit board and into the brake light.
It needs to be one like in the second link, as they are soldered to the PCB
#13: Re: Weird Brake Light Problem Author: V9977, Location: Athens, GreecePosted: Sat May 28, 2011 11:37 am ---- Also, why are you using a shunt resistor for the 3rd brake light for LED's?
I thought it was only required for indicators so it doesn't flash fast because
it thinks a bulb has blown, OR CAN/VAN systems?
EDIT: which pcb?
#14: Re: Weird Brake Light Problem Author: Lee, Location: EnglandPosted: Sat May 28, 2011 11:38 am ---- 12volts fried the LED's. Need a resistor every 3-5 LED's. Got them in my front lights as well
#15: Re: Weird Brake Light Problem Author: Lee, Location: EnglandPosted: Sat May 28, 2011 11:39 am ----
V9977 wrote:
Also, why are you using a shunt resistor for the 3rd brake light for LED's?
I thought it was only required for indicators so it doesn't flash fast because
it thinks a bulb has blown, OR CAN/VAN systems?
EDIT: which pcb?
The circuit board, that the LED's and resistors are soldered too in the third brake light.
Resistor for every 4 LED's
#16: Re: Weird Brake Light Problem Author: V9977, Location: Athens, GreecePosted: Sat May 28, 2011 11:42 am ---- Ah OK.
Then you're connecting is series to drop the current.. 1W should be fine and no heating.
18 Ohms sounds way too low.. Should be 1.8K or 180 Ohms at lowest I would think.
Can you check the other ones?
#17: Re: Weird Brake Light Problem Author: Lee, Location: EnglandPosted: Sat May 28, 2011 11:44 am ---- Other ones are fine. They are all the same. Had the brake light fitted 2 years, and its just gone.
Ironically, one blew in that, and one went in my front lights. Not having any look with electrics on the car recently. Had to get a new battery last week as well
#18: Re: Weird Brake Light Problem Author: V9977, Location: Athens, GreecePosted: Sat May 28, 2011 11:45 am ---- Wait a minute, it is 180 Ohms = Brown-grey-brown my bad!
Could need 1.8K, check the others if you can.
I still think the switch is probably gone though.
#19: Re: Weird Brake Light Problem Author: Lee, Location: EnglandPosted: Sat May 28, 2011 11:48 am ---- Yeah I think it probably is.
As even with the third brake light disconnected, I'm still getting the same voltage. Makes me wonder if some water got on the connector and it shorted it.
#20: Re: Weird Brake Light Problem Author: V9977, Location: Athens, GreecePosted: Sat May 28, 2011 11:50 am ----
Lee wrote:
Yeah I think it probably is.
As even with the third brake light disconnected, I'm still getting the same voltage. Makes me wonder if some water got on the connector and it shorted it.
Wouldn't think so that quick..
Anyway I hope you sort it mate. No brake lights is considered bad, even over here.
#21: Re: Weird Brake Light Problem Author: Lee, Location: EnglandPosted: Sat May 28, 2011 11:52 am ---- Yeah, not the best lights to not have working
Bank holiday as well, so nothings open till Tuesday
#22: Re: Weird Brake Light Problem Author: V9977, Location: Athens, GreecePosted: Sat May 28, 2011 11:54 am ---- Hope the loom is OK.
#23: Re: Weird Brake Light Problem Author: Lee, Location: EnglandPosted: Sat May 28, 2011 12:27 pm ---- Loom I'm not overly fussed about, because I can easily rewire that, only half a dozen wires.
And if worse comes to worse, I have a spare cabin loom anyway.
#24: Re: Weird Brake Light Problem Author: Timon2210, Location: PalestinePosted: Sat May 28, 2011 2:28 pm ---- I believe what caused your problem was a short circuit cause by the 3rd brake light when you refitted it,maybe you got a "naked" wire somewhere...hehe,check for it,the heat in wires is always cause by a short.
#25: Re: Weird Brake Light Problem Author: V9977, Location: Athens, GreecePosted: Wed Jun 01, 2011 5:13 am ---- Any luck with this yet Lee?
#26: Re: Weird Brake Light Problem Author: Lee, Location: EnglandPosted: Wed Jun 01, 2011 11:05 am ---- Yeah fixed it.
Just rewired it all
Took about 30 mins
#27: Re: Weird Brake Light Problem Author: V9977, Location: Athens, GreecePosted: Wed Jun 01, 2011 11:45 am ----
Lee wrote:
Yeah fixed it.
Just rewired it all
Took about 30 mins
Cool.
Quick question:
I have one of these fitted for the past couple of years and works a treat.
However, I'm now thinking of replacing the 501's with LED's so as to set it on fast mode (strobe) which will look a bit neater (see video).
Will need a droping resistor, but which of these are better for a standard 3rd light unit?
#28: Re: Weird Brake Light Problem Author: Lee, Location: EnglandPosted: Wed Jun 01, 2011 12:01 pm ---- The standard one uses white bulbs I think, rather than red bulbs.
#32: Re: Weird Brake Light Problem Author: Lee, Location: EnglandPosted: Wed Jun 01, 2011 12:35 pm ---- The cheek
#33: Re: Weird Brake Light Problem Author: Harry, Location: StaffordPosted: Wed Jun 01, 2011 12:42 pm ---- You know it's true keep that one it's the best
#34: Re: Weird Brake Light Problem Author: Lee, Location: EnglandPosted: Wed Jun 01, 2011 12:43 pm ---- It's what happens when you get bored
#35: Re: Weird Brake Light Problem Author: V9977, Location: Athens, GreecePosted: Wed Jun 01, 2011 1:05 pm ---- ??!!!
What happened to the 'no-flashing lights appart from indicators' rule over there??
Looks totaly cool, I'm well impressed I have to say..
Also quite useful in some situations no?
#36: Re: Weird Brake Light Problem Author: Lee, Location: EnglandPosted: Wed Jun 01, 2011 1:08 pm ---- Instead of the hazards
Fancied a change
#37: Re: Weird Brake Light Problem Author: V9977, Location: Athens, GreecePosted: Wed Jun 01, 2011 1:11 pm ----
Lee wrote:
Instead of the hazards
Fancied a change
Hmm..
So how do you pick-off the 'hazards-on' signal, or do you use a different switch?
#38: Re: Weird Brake Light Problem Author: Ste, Location: Hull -or- The World Of Info CodePosted: Wed Jun 01, 2011 1:12 pm ---- lmao Lee thats ace
#39: Re: Weird Brake Light Problem Author: Lee, Location: EnglandPosted: Wed Jun 01, 2011 1:39 pm ----
V9977 wrote:
Lee wrote:
Instead of the hazards
Fancied a change
Hmm..
So how do you pick-off the 'hazards-on' signal, or do you use a different switch?
Just rewired it all
And just used some diodes to protect the existing circuit
#40: Re: Weird Brake Light Problem Author: V9977, Location: Athens, GreecePosted: Wed Jun 01, 2011 1:43 pm ----
Lee wrote:
V9977 wrote:
Lee wrote:
Instead of the hazards
Fancied a change
Hmm..
So how do you pick-off the 'hazards-on' signal, or do you use a different switch?
Just rewired it all
And just used some diodes to protect the existing circuit
Cool.
I'm thinking of using diodes to keep the rear-sidelight filaments on when the brake is applied. That will give 25% brighter brake lights even with standard bulbs.
Forget putting a how-to on here though....
#41: Re: Weird Brake Light Problem Author: Lee, Location: EnglandPosted: Wed Jun 01, 2011 1:51 pm ---- Yep, uniqueness no more when you post a how too
#42: Re: Weird Brake Light Problem Author: V9977, Location: Athens, GreecePosted: Wed Jun 01, 2011 1:56 pm ----
Lee wrote:
Yep, uniqueness no more when you post a how too
Not really fussed about that.
It seems that alot of times people disagree with my way of doing things.
Oh well.
At least its sunny.
#43: Re: Weird Brake Light Problem Author: Lee, Location: EnglandPosted: Wed Jun 01, 2011 2:01 pm ---- Disagreements always make things more fun
#44: Re: Weird Brake Light Problem Author: V9977, Location: Athens, GreecePosted: Wed Jun 01, 2011 2:04 pm ----
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