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  • 1996 - 2004 SN95 Mustang -General/Talk-
  • SN95 4.6L Mustang Tech

Brake Lights

  • Thread starter Thread starter gt_orange
  • Start date Start date Jul 4, 2012

gt_orange

New Member
Jul 4, 2012
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1
Mountain Grove,Mo
Jul 4, 2012
#1
  • Jul 4, 2012
  • #1

I have a 2000 gt mustang, bought the car in 2006, today I noticed the brake lights are not working, the flashers/headlight/parklights all work. the third brake light works when brake is applied. fuses as all in working order, cruse control works aswell. any ideas??
 
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phatboy5015

Member
Feb 5, 2012
60
1
9
Jul 4, 2012
#2
  • Jul 4, 2012
  • #2
If the third brake light works, it's probably just bulbs.
 

wmburns

SN Certified Technician
Aug 14, 2009
5,892
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204
Houston Texas
Jul 4, 2012
#3
  • Jul 4, 2012
  • #3
Once the bulbs have been confirmed, then check the multi-function switch.
 
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phatboy5015

Member
Feb 5, 2012
60
1
9
Jul 4, 2012
#4
  • Jul 4, 2012
  • #4
wmburns said:
Once the bulbs have been confirmed, then check the multi-function switch.
Click to expand...
What would that have to do with anything? If the third brake light works, then all the switches/relays are working. It's either bulbs or the harnesses behind the taillights.
 

wmburns

SN Certified Technician
Aug 14, 2009
5,892
514
204
Houston Texas
Jul 4, 2012
#5
  • Jul 4, 2012
  • #5
phatboy5015 said:
What would that have to do with anything? If the third brake light works, then all the switches/relays are working. It's either bulbs or the harnesses behind the taillights.
Click to expand...
Not true.

The power for the 3rd brake light goes directly from the brake switch to the 3rd brake light. So you are correct that a working 3rd brake light "proves" the fuse and the brake switch.

However, the power for the brake lights themselves goes through the multi-function switch. The multi-function switch is needed to make the hazard lights blink and to control when the brakes are applied and the turn signal is on.

The wiring diagrams are very clear about that.
 
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phatboy5015

Member
Feb 5, 2012
60
1
9
Jul 4, 2012
#6
  • Jul 4, 2012
  • #6
wmburns said:
Not true.

The power for the 3rd brake light goes directly from the brake switch to the 3rd brake light. So you are correct that a working 3rd brake light "proves" the fuse and the brake switch.

However, the power for the brake lights themselves goes through the multi-function switch. The multi-function switch is needed to make the hazard lights blink and to control when the brakes are applied and the turn signal is on.

The wiring diagrams are very clear about that.
Click to expand...
Ahh.. I stand corrected.. I didn't think about that.
 

gt_orange

New Member
Jul 4, 2012
10
0
1
Mountain Grove,Mo
Jul 5, 2012
#7
  • Jul 5, 2012
  • #7
thanks guys, I will be buying a multi-function switch in the morning, the third brake light threw me for a loop. if its getting its power from different locations then that narrows it down. it hit 100000 2 months ago and nothing but problems since, I have rebuild the bottom end, the traction lock, and driving home from shooting fireworks I lost all gears. I had to stop and shut the car off then was able to get into 2nd to make it the last mile.
 

wmburns

SN Certified Technician
Aug 14, 2009
5,892
514
204
Houston Texas
Jul 5, 2012
#8
  • Jul 5, 2012
  • #8
Before you buy a multi-function switch, try activating the hazard lights multiple times. Sometimes using the switch will "clean" the contacts and restore function.

Note, the multi-function switch can be rebuilt. If you decide to tackle, take tons of pictures. Once the switch is apart, clean the switch contacts. Very lightly sand and re-grease the terminals with electrical di-electric grease.
 

gt_orange

New Member
Jul 4, 2012
10
0
1
Mountain Grove,Mo
Jul 5, 2012
#9
  • Jul 5, 2012
  • #9
I will, i rebuild the driver window motor last week, works good as new. I should post pics of that to
 

gt_orange

New Member
Jul 4, 2012
10
0
1
Mountain Grove,Mo
Jul 5, 2012
#10
  • Jul 5, 2012
  • #10
View attachment 72524
Found the problem, 2 of the wires backed out, easy fix
 
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