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Dan
Dan, Technician
Category: Chevy
Satisfied Customers: 23590
Experience:  Independent Shop Experience, 2 Year Automotive Diploma, & Access to Information Database
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I have a 2004 Chevy Colorado.I have no brake lights I

Customer Question

I have a 2004 Chevy Colorado.I have no brake lights I replaced the switch and checked the fuse what else can cause this problem?
Submitted: 10 months ago.
Category: Chevy
Expert:  Randall C replied 10 months ago.

Hello, do you have a testlight or volt meter? we need to do some tests

Customer: replied 10 months ago.
I have a volt meter
Expert:  Randall C replied 10 months ago.

WE have to start with basics, Get to the brake light switch, probe the orange wire with key off, I need the volts, then hold brake pedal down and probe the LT blue? wire and need the voltage readings, I think i am correct on wire colors, you leave switch plugged in, I need you to backprobe the 2 wires at the connector at switch

Customer: replied 10 months ago.
11.8 vdc at orange and 8.5 at blue with pedal depressed.
Expert:  Randall C replied 10 months ago.

odd, both should be battery voltage, nothing less, I am unsure why the low volts , is battery fully charged? can you remove the stop fuse and probe the fuse terminals and see if battery voltage there

Customer: replied 10 months ago.
Not sure but it doesn't appear to be getting any power to the fuse
Expert:  Randall C replied 10 months ago.

that would not be possible if you have 11.8 at orange wire at switch, You removed the stop fuse, probed the fuse terminals no power to either?

Customer: replied 10 months ago.
Nothing constant
Customer: replied 10 months ago.
I don't seem to be getting a good connection at the terminal itself
Expert:  Randall C replied 10 months ago.

im going to opt out, i am unsure which direction to go with non tests

Expert:  Dan replied 10 months ago.

Disconnect brake light switch and jump orange wire to blue wire and let me know if that turns on brake lights. Thanks.

Customer: replied 10 months ago.
No it didn't help still nothing but taillight
Expert:  Dan replied 10 months ago.

Are you 100% sure you have voltage on orange wire?

Customer: replied 10 months ago.
What about the loose connection at the fuse box
Expert:  Dan replied 10 months ago.

If connection was loose voltage would be low on orange wire. Are you sure you have good voltage on orange wire?

Customer: replied 10 months ago.
Getting nothing at the orange wire now
Customer: replied 10 months ago.
Not getting a good connection at the brake fuse since probing it
Expert:  Dan replied 10 months ago.

This wire gets voltage from the 20 amp STOP fuse in location 1 of fusebox under the hood. Check to see if fuse is good if so remove/reinsert fuse a couple times incase it has a poor connection. If that doesnt help check connections at fusebox. If still no good then replace orange wire that goes from fuse box to switch. Let me know how it goes or if you have more questions. Thanks.

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Here is a wiring diagram to help with testing.

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https://www.dropbox.com/s/rc7gawi9rf5u0hz/blsww.pdf?dl=0

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