View Full Version : third brake light
wprocomp
11-05-2003, 04:03 PM
my third brake light is not coming on and its turning on my brake lamp light on the gauges...I ahve checked all the fuses and have even got a new socket and bulb,but it still isnt lighting up,,any ideas?
Which warning light is coming on? The one in the diagram of car with the door open light? Or the one that says BRAKE? Any way I don't think a burnt out high mount brake light will turn on the warning light. I think it will turn on only if one of the two brake/tail lights burn out.
Illicit3rdgenRacer
11-05-2003, 04:38 PM
no if tha brake light on your console comes on that means your are low on brake fluid happend to me plenty of times and it comes on when your parking brake is up and for your third brake light you might wanna check your brake light switch on your brake pedal it might be faulty haev some one look at it. that might be tha prob but good luck with it
Yep, that's why I asked which light was coming on. If it is the one that says BRAKE as stated above check your fluid level, condition of pads or parking brake switch.
If the light in the car diagram is on check the bulbs in the back in the brake/ tail lights.
High mount light not coming on check for 12 volts and ground at the socket.
Neuspeed87lx
11-05-2003, 07:51 PM
if all else fails check resistance of the third brake light circuit....
wprocomp
11-06-2003, 09:58 AM
yeah i havent done that yet so I will do it today...but the brake fluid is fine,and since when did the brake light come on when your pads a worn?
Your BRAKE light might come on if your pads are really worn because the fluid level in the resevior might be low due to the caliper being expanded. I mean if your fluid level is low and there is no leak it's got to be going somewhere. Maybe into the calipers if the pads are low. I might be wrong but it was a thought.
wprocomp
11-06-2003, 03:36 PM
well i did check the resistance of the light and it has no power...now there is no fuse for the third brake light that could find so it cant be that...and i checked the brake light switch on the pedal and even moved forward a little but it still dont work..fack
Neuspeed87lx
11-06-2003, 07:01 PM
checking the resistance of the bulb wount tell you if there is power or not ....it will just show you if there is a problem with the wiring .... like an open or a short ....
TWOLOUDNPROUD
11-06-2003, 07:50 PM
Go to the passenger side taillight the black box on the in side of the taillight is the one that controls the thrid break the green with wite strip is the wire that go's to the light that box might be bad
cjacks
11-20-2003, 03:56 PM
Hi guys. I am so happy I found this site. My daughter has an '89 Honda Accord with a brake condition.
Here is what is happening: Gear can not be moved from Park (unless key over ride is used). When brake pedal is pressed, the light that looks like a door ajar light )the light on the right side of the brake light that comes on when the emergency brake is placed in the up position) comes on, and no brake lights. I have checked the fuses under the dash and they are all ok. I checked the fuses in the engine compartment and the 20amp fuse blows out (replaced it twice). The fuse location is labeled STOP, HORN (seat belt retraction). What does STOP on the fuse label stand for? I suspect a short somewhere but have not a clue where to start looking any sugestions appreciated!
If I understand this, the light on the dash in the car diagram is coming on when you press the brakes. Well if so that is an indicator that there is problem with brake lights (usually a burnt out bulb).
Does the fuse blow right away? Does it blow only after you press the brake?
If it blows only after the brake is pressed, there is a short in the brake light circuit. It could be anything from a shorted bulb, shorted socket, shorted wire or bad sensor.
First I would pull out all the bulbs and check the sockets for water, corrosion, or a short.
With the bulbs out see if the fuse still blows.
cjacks
11-21-2003, 11:49 AM
I know this is odd but no it is nether the car diagram light or the brake light. It is a door ajar light on the right side of the brake lite that comes on as soon as the peddle is pressed. I know it sounds odd. given the fuse is blowing tells me maybe it is shorting out with a wire in the door ajar system or a circuit panel that has those two things in common?
cjacks
11-21-2003, 03:39 PM
Update. I disconneted both brake light system sensors. Fuse did not blow. I re-connected right sensor, fuse did not blow then I re-connected the left brake sensor and the fuse blew.
Good chance that sensor is bad. But before I would change it I would pull the bulbs and check the sockets for moisture or corrosion. And maybe even for the hell of it (if you have spare fuses) with the bulbs out try and plug the sensor back in and see if it still blows.
cjacks
11-21-2003, 04:00 PM
Yes I had all the bulbs out and the fuse still blows with that LH sensor pluged in. Is there any way to read the sensor to check it?
cjacks
11-21-2003, 04:19 PM
I took the left sensor and plugged in to the right sensors spot. Fuse did not blow (no sensor plugged in left spot)
I don't think they are interchangeable. Left has 5 pins and right has 6 pins. The right connects to the left and the left connects to the indicator on dash.
Do you have a multimeter?
I pulled a spare out of the garage to buzz out. Here's what I found:
on the top row there should be only 2 pins, both of them didn't buzz out to any other pin. I did 1 at a time and went to every pin on the connector and there was no continuity.
OK the bottom row should have 3 pins: All three of these pins I read a little resistance to each on the bottom row. I believe that they are reading thru coils of relays.
So recap: the 2 top pins = no continuity to any pins.
The 3 bottom pins = small resistance to each other only but no continuity to the top pins.
cjacks
11-22-2003, 06:09 AM
my top 2 pin results were same as yours. but when I checked the bottom set of pins I got continuity from all 3 bottom pins to the top left pin (with the 2 pins are on top) no continuity on the top right pin from either bottom 3 pins.
WITH PIN A BEING THE 1ST/left PIN IN THE 2 PIN ROW FACING THE TOP
PIN A = NO CONTINUITY TO ANY PIN
PIN B = NO CONTINUITY TO ANY PIN
PIN C = CONTINUITY TO ALL PINS EXCEPT PIN B (INCLUDES PIN A)
PIN D = CONTINUITY TO ALL PINS EXCEPT PIN B (INCLUDES PIN A)
PIN E = CONTINUITY TO ALL PINS EXCEPT PIN B (INCLUDES PIN A)
How can we be sure this is the same sensor? This one is brown with the letters DO AD18 stamped on the back plastic case. and the numbers S-321(can not read the rest) printed on the circuit card. I took the card out of the plastic case and inspectd it, it looks ok no burn marks or anything. Of course not sure about the diode or cathode whatever it is, but it looks ok.
Ok I think they are the same. My circuit card reads S-3216D.
Any way your diode might be bad. Read across the diode in resistance (not continuity, no beeper).
Red lead on top of diode (2 pin side of diode) Black lead bottom of diode (3 pin side) = about 4 M ohms.
Switch leads.
Black lead on top of diode- Red lead on bottom of diode = OPEN
In othe words you should be able to read thru in one direction but not in the other direction. It is a blocking diode, current should only flow in one direction.
If you decide to try and change the diode, be careful and take note what side the line is on. If you put the new one in backwards you will still have the same problem.
cjacks
11-22-2003, 07:55 AM
I did some reading on the plug. On the left plug I get volts at one of the pins when ignition is in "start". I get an additional live wire when the brake pedal is pressed. I understand the brake switch, but where is the come from the ignition switch?
If you are talking about having ign voltage on the sensor plug, I don't think it belongs there. What wire do you have ign. voltage on?
Sorry I was wrong. I just checked my car and I do have ign voltage on the white/green wire.
cjacks
11-22-2003, 08:16 AM
That seems to check ok. looks ok also
cjacks
11-22-2003, 08:18 AM
That's what I have also. White/Green voltage with ign in on position. Well there must be a short somewhere. Any sugestions on where to start looking?
cjacks
11-22-2003, 10:36 AM
Where is the fuse that controls instrument display (warning lights, gages ect)? I must have blown it. No instrument activity.
88LXi/87CRXSi
11-22-2003, 11:43 AM
Originally posted by cjacks
Where is the fuse that controls instrument display (warning lights, gages ect)?
Fuse #2 in the dash fusebox. Click the link below for a circuit schematic of the brake lights. Maybe it might help for in tracking down that short!
Brake Light Circuit Schematic (http://members.nccw.net/heywood/Brake%20Lights%20Circuit%20Schematic.jpg)
cjacks
11-22-2003, 12:53 PM
Where can I get a sensor? Would rather change it and elliminate it as a cause.
You can always try your local junk yard.
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