On my 04 Coupe the driver side brake light goes off when apply brakes if car lights are on but works fine if lights are off. Also the “light out” symbol shows on dash every time I press brakes in daytime but stays on if lights are on. Can someone Please help me.. I would be very grateful. Plus the third light does not work but when I unplugged it and used my volt meter it lit up. Anyone got suggestions what I can do?

 

You have the wrong bulb in the stop light, or it is in 180 degrees out of position. change the stop bulbs with one another and see what happens and check that they have the same number on them.

The third brake light can be repaired sometimes, there is a repair company mentioned on the forum somewhere.

 

Cadillac LED Replacement 3rd Brake Light, Third Brakelights For Escalade, ESV, Escalade EXT, Avalanche LTZ, Chrysler Crossfire, 2010-2011 SAAB 9-5, 2015-2019 GMC Yukon, Yukon Denali Tail Light Repair

 

In February you were talking about the instrument brake light or the bulb out indicator, what bulb are we talking about this time?

 

The same problem of driver side brake light goes off when I apply brakes with car lights turned on but works perfect when car lights are off.!!! But the “light out” dash light comes on every time I apply brakes regardless!!!! Please help me someone. Sincere appreciation, Yvonne

 

Yvonne, first make sure the correct bulb is installed (the brake light bulb is a two filament 21/5W), take out the old bulb by pushing in slightly and turning it (I believe) to the left to bypass the locking design of the socket. Take the new 21/5W bulb and install it into the socket by sliding the pins down the slots in the socket. Then turning the bulb (I believe this time to the right), into its locked position (do not force the bulb into the socket, it should go only one way since the pins on the base of the bulb are offset from the end). If you cannot get the bulb to turn after sliding into the socket you might have the bulb 180 degrees out. There is a 50/50 chance it'll go in correctly every time. IF the base is damaged, your going to have to make sure the bulb is correctly inserted (if someone else installed a bulb wrong it could have damaged the socket locking pin locations.

About your third light situation, you mentioned " third light does not work but when I unplugged it and used my volt meter it lit up ", what lit up? The third brake light? If it lit up correctly when you used a voltmeter, maybe the connector is damaged in some way. That may be a lot easier to fix, than sending it in somewhere to be repaired. Appreciate a more detailed description of the third light issue, ok?

 

The dash light probably comes on because the third brake light is not working.
What is the bulb number you have in the two brake light sockets?
Edit
You replied that you were using Sylvania #7528 - 21/5W, however on the blister pack it says 25/6W, this seems OK with the following PDF CLICK
You say In the past, people have had trouble when a broken bulb filament falls onto the other filament, could that be your troubles?