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My brake lights on my 1991 Eldorado just quit working. I have checked the fuse in the glove box, the bulbs, and the switch on the brake pedal with my voltmeter an everything seems OK. The tail lights (which share a double filiment bulb) are working. Is there another fuse that I may be missing somewhere? Any help would be appreciated.

john.

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jfhoward1 said:
My brake lights on my 1991 Eldorado just quit working. I have checked the fuse in the glove box, the bulbs, and the switch on the brake pedal with my voltmeter an everything seems OK. The tail lights (which share a double filiment bulb) are working. Is there another fuse that I may be missing somewhere? Any help would be appreciated.

john.

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Hey John,
Does the high-mount brake lamp work? ETCs have a DIRECT feed to the high-mount brake lamp from the brake switch.
If your car's NOT an ETC then ALL the brake lamps and signals are controlled via the Hazard/Turn signal module mounted next to the column. That's probably your problem.
 

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Katshot said:
Hey John,
Does the high-mount brake lamp work? ETCs have a DIRECT feed to the high-mount brake lamp from the brake switch.
If your car's NOT an ETC then ALL the brake lamps and signals are controlled via the Hazard/Turn signal module mounted next to the column. That's probably your problem.
Kevin: Thanks for your input. Yes, mine is a ETC. The high-mount is not working either. Please tell me a little more about how the direct feed works. I just tried replacing the brake pedal switch and it didn't help.

john...
 

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From what I remember and what I'm seeing on the schematic, you have 2 brake switches, or at least 2 circuits through 1 switch. One circuit is for the VCC control and the other is for the brakes and cruise control. For some reason, I'm having a hard time locating both switches on the schematics but there is definate references to those 3 control circuits. Is it possible that you replaced and/or have been troubleshooting the wrong brake switch?
According to this schematic, the ETC has a direct circuit that goes from the brake switch to the high-mount brake lamp and the other lamps are controlled via the module I mentioned before. On the standard Eldo, ALL brake lamps are contolled via the module. So since you have a ETC, I would assume that a non-functional high-mount lamp would be pointing to either the switch or power source for it (fuse).
 

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Katshot said:
From what I remember and what I'm seeing on the schematic, you have 2 brake switches, or at least 2 circuits through 1 switch. One circuit is for the VCC control and the other is for the brakes and cruise control. For some reason, I'm having a hard time locating both switches on the schematics but there is definate references to those 3 control circuits. Is it possible that you replaced and/or have been troubleshooting the wrong brake switch?
According to this schematic, the ETC has a direct circuit that goes from the brake switch to the high-mount brake lamp and the other lamps are controlled via the module I mentioned before. On the standard Eldo, ALL brake lamps are contolled via the module. So since you have a ETC, I would assume that a non-functional high-mount lamp would be pointing to either the switch or power source for it (fuse).
I know I must be missing something. The switch on the brake pedal has two circuits. The larger clip with orange and light blue leads (I'm assuming this is for the brake lights) with some type of diode with a red wire attached to both leads . The other is a smaller clip with brown and grey leads (I'm assuming this is the cruise). I tested the cruise and it cuts off when I brake. You mentioned a VCC. I don't know what that is.
I'm 100% about the fuse and I've replaced the switch. I was thinking that it may be a broken wire, but I don't think the tail lights would work if that was the case. I have not checked the control module you referenced. could you give me any guidance on how to check it?

Thank you for you help!

John...
 

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Take a test light and check to see if you have power at the circuit with the orange and blue wires. You should have power at the orange I think (I'm home and don't have the schematic in front of me), and power at both when you press the pedal (closing the switch).
If you don't have power there, you have a fuse and/or wiring problem. If you have power and it flows through the switch when closed, the problem is probably a bad connection or wire from there to the back. Good chance it's in the trunk.
 

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Discussion Starter #7
Katshot said:
Take a test light and check to see if you have power at the circuit with the orange and blue wires. You should have power at the orange I think (I'm home and don't have the schematic in front of me), and power at both when you press the pedal (closing the switch).
If you don't have power there, you have a fuse and/or wiring problem. If you have power and it flows through the switch when closed, the problem is probably a bad connection or wire from there to the back. Good chance it's in the trunk.
I have power at the circuit and I traced the wires to the box in the trunk where all the wires connect. I unpluged it and comfirmed power to the orange wire and blue had power(actually there are two blue wires but both had power). My next step is to determine if power is coming out of that box. The wires change color out of the box so I'm not sure the best way to accomplish this. Any ideas? I've concluded that it must be a wiring problem. Last question - If a wire is broken, would all three brake lights fail and would the tail lights work.

Thanks again for your help.
 

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jfhoward1 said:
I have power at the circuit and I traced the wires to the box in the trunk where all the wires connect. I unpluged it and comfirmed power to the orange wire and blue had power(actually there are two blue wires but both had power). My next step is to determine if power is coming out of that box. The wires change color out of the box so I'm not sure the best way to accomplish this. Any ideas? I've concluded that it must be a wiring problem. Last question - If a wire is broken, would all three brake lights fail and would the tail lights work.

Thanks again for your help.

Kevin:

THEY WORK! OK get this, after three days of checking fuses, rearanging all the relays, taking apart the tail lights, replacing the brake switch and tracing the wrong and right wires, I was about to take in into the dealer here in Raleigh. Then I thought about the two leads into the switch (cruise and brakles). I was not 100% sure which was the cruise, so I disconected the small clip from the switch and drove around the block to make sure the cruise did not work (which it didn't). When I pulled back into my driveway...

The brake lights worked!

I hooked the clip back in and they still work. I don't get it, but I'll take it. Thanks for all your help and maybe this will help someone in the future.

John...
 
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