Brake lights wont work on my 97 G.T. Convertible.

2nd Stang · 06-30-2003

Ok here is the deal. !997 Mustang GT Convert. Brake lights wont light up (not even trunk mounted). All bulbs are fine. Replaced Brake light switch on Brake pedal and power is going to switch. Still wont Work. Blinkers or hazards wont work. Replaced Flasher unit. Still wont Work.
Here is the Strange part, On the wiring diagram in the book i need Fuse #1 and #9 for the Blinker/hazard and Brake lights. #1 fuse installed...#9 fuse installed and the Hazards start to flash. Turn Hazard switch on and off and still flashing. Remove switch and still flashing. Remove #9 Fuse and stop flashing.
Could there be a crossed wire?
Dont know what to do next.
All other parts work fine, interior lights, electric windows, elec. top, Radio does seem to have a short.... but all is fine other than that!!
Please Help

1998GT · 07-01-2003

I dont know if this helps but my brake lights stopped working for a lil bit, it was a bad fuse under the dash.. No need to buy another, there were like 3 extras in the box.

jtweathers · 07-05-2003

Sound to me like you hazards wires might crossed up somewhere. They should not flash with the switch off. Did this start recently?
Next question. With the flashers on... can you hit the brake pedal and get a constant brake light. If so like I said its somewere in the flasher circuit
Next question, do you taillights work (headlights on? and if so are they all the same intensity?
Wish I was there I know I could fix your problem in a few minutes with a multimeter. Keep to the basics and follow the schematic step by step measuring every connection point until it changes. I would start at the fuse box then go to the switches tracing every wire indiviudally, then to the lights. Also check all ground wires.Hope this helps. Last rule, and most important... never cut a wire unless you are sure it will fix the problem. This causes future problems (Opens) with corrosion due to water getting to the conductor of the wires.
Good Luck
Jtweathers
PS If your radio is shorted take it out ASAP.

2003GT · 07-05-2003

JTWeathers is right! Start testing. Buy a test light or a good multimeter, and simply start tracking wires. The fuse box is a good place to start. If you have power there keep moving towards your lights if you dont go back up towards the switches. Its as easy as following the wires and watching for your test light to light up. Good Luck!

2003GT · 07-06-2003

Have you installed any chips recently? I had some minor electrical problems after installing a diablo sport chip.

BlueStreak03 · 07-06-2003

Yeah man, go to Lowe's hardware and pick up a multimete, you can get a decent one for about 30 bucks. then pull out the schematic and do what's called 'half-stepping' pick a spot on the diagram that is about halfway through the ciruit. Figure out what kinds of readings you should get at the point under certain conditions. Test that point. If all is fine there, move down stream on the circuit some and keep doing that until you find the cause. After spending 3 years as an electrician on the Enterprise, I can say it sounds like you have a short to ground or to another wire. Good luck and happ hunting.

2nd Stang · 07-06-2003

OK, Trunk mounted light had 2 bulbs missing, Fixed that problem!!
I am the 3rd owner of this car, 1st owner had Flowmaster, K&N flilter, Roll Bar w/LIght, and Alpine stereo among other things installed. My Ex- sister in-law was second owner. Did not know a thing about cars. The hazard lights started blinking on their own, she pulled the #9 fuse and they stopped working, so did the BRAKE LIGHTS!!! Any way, i am figuring out little by little. She took it some where (to have the lights fixed) and they told her the radio had a short in it and helped themselves to AMP and the Speakers from the trunk. Thats why the Stereo doesn't work!!!! and yes she let them do it!

Now on to the lights. Thanks for all the replies!! Appreciate them very much. I am new to ELECTRICAL repair and all advice helps!!
When the flashers are on There is NO BRAKE LIGHT from the 2 main brake light groups, only the roll bar light and the trunk mount.When the headlights are on it is the same thing. Could it be the MULTI FUNCTION SWITCH located next to the Fuse box under the Steering wheel?? The wiring diagram i have has all of these wires routing through this box. MY husband purchased a multimeter, and i am trying to learn how to use it. Thanks again for the advice.

2003GT · 07-08-2003

Turn the multimeter to D.C.(this will show you the voltage so you can ensure your getting power) When passing through fuses or switches use the continuity setting just touch the wires on opposite sides of the switch or fuse and it should beep or show a setting of 0.00. This will show you if power is getting through the switch or not. Just make sure you do it with the fuse in and have the brakes pressed. Its also useful when get into a big group of wires of if you cant see where the wire goes. You can always add more wires to the connectors if they arent long enough. Just a thought.....Try removing the fuse that runs your stereo than put the fuse for the brakes back and in and try it. Just a guess. If it works youll know for sure its a short in your stereo, if not than it was worth a try and yes the problem could still be in the stereo. Also make sure you check the wires very carefully for nicks or frays, and if its dirty in there clean up your grounds with a small file or wire brush. I wish I was there I could really help........

2003GT · 07-08-2003

Oh also, did they take all the wires for the stereo components out when they took it out? You might have a hot wire floating around touching something that its not supposed to.

2nd Stang · 07-09-2003

Problem solved!!!! The hazard light switch was bad, it was stuck in the on position, Fooled with it awhile and finally got it unstuck. Aparantly, Brake lights don't function when the hazard lights are on. (My 2003 Pathfinder works differently, The brake lights will work when flashers are on!) Replace the Flasher unit and the fuse, Now everyting is fine. Also there was a bad wire with the radio, it pulled to much power and kept blowing the fuse for the lights, thats why my sister in-law gave away the amp and speakers. Not to Bright. Just to add to the sister in-law thing, she hit an Armadillo and lost a tail pipe....Took the car to get the oil and K&N air filter changed and they didn't replace the filter, they duct taped the end shut!! but charged her for the filter. Funny thing is she is now the proud owner of a 2003 Mustang Cobra!
Oh the humanity!! Poor car!!
Thanks again for all of the HELP!!
And Thanks 2003GT for the tips on the Multimeter!

BlueStreak03 · 07-09-2003

Do us all a favor and get that Cobra away from her. Someone like that doesn't deserve a machine of that caliber. Give yours back to her and tell her you're doing her a favor, which you really are.