I have a 71 cutlass and I have been having this problem for awhile now and can't figure out the problem. I have seen many threads but I have not seen any that diagnose the problem that I am having. Every time I press the brakes, raise or lower the convertible top the radio shuts off and turns back on. I also have 2 amps installed in the car. The amp with the sub connected to it continues to play while the other amp with the mid range speakers shuts off. I have replaced the battery, alternator, fuse panal and wiring harness but I still have the same issue. I have checked the brake light housing but didn't see a ground stud for the wiring. Also I recently noticed that the interior dash lights illuminate when I press the brake also. Does anyone have an idea what the issue is because I have ran out of options

 

I have a 71 cutlass and I have been having this problem for awhile now and can't figure out the problem. I have seen many threads but I have not seen any that diagnose the problem that I am having. Every time I press the brakes, raise or lower the convertible top the radio shuts off and turns back on. I also have 2 amps installed in the car. The amp with the sub connected to it continues to play while the other amp with the mid range speakers shuts off. I have replaced the battery, alternator, fuse panal and wiring harness but I still have the same issue. I have checked the brake light housing but didn't see a ground stud for the wiring. Also I recently noticed that the interior dash lights illuminate when I press the brake also. Does anyone have an idea what the issue is because I have ran out of options

 

Obviously you still have wiring issues. I'd say something is spliced somewhere it shouldn't be, or you've got something rubbing against something it shouldn't. I think you'll have to start at the battery & check every inch of wire, connection, connector, splice, split, what ever till you find something that doesn't look right?
Good luck. Maybe something in the headlight switch or steering column area?

 

I will try the steering column because that is the only thing I have not checked, thanks

 

I suspect wiring and since you mentioned that you replaced the wiring, with what? Did you get a harness from a used vehicle? Did you replace the complete harness and was it a reproduction or an aftermarket generic? I do know if the brake lights illuminate when you press the brake pedal then you don't have to worry about a ground stud for the brake lamp housings UNLESS the chassis/frame ground is bad due to corrosion. Yhis would cause the brake lamps to not illuminate at least intermittently so I don't think this is your problem. I sounds like you have the dash light supply incorrectly routed and/or the radio supply incorrectly routed. Since you have added aftermarket amplifiers be sure you have a good source and ground and that they are correctly fused and have no loose or intermittent physical connections. They need to have their own separate circuits. Moving this thread to the electrical forum.

 

The harness that was installed was new from keep it clean wiring. I replaced the wiring because their were alot of splices in the original harness and before when I would press the brakes the park lights would light up but since the new harness was installed I don't have that problem anymore. The amps have a good ground and the power is ran to a capacitor then to the amplifiers but I will check it again as well.

 

Do you know what would be checked at the steering column to see if there is a problem with it. Will I be checking for continuity or power issues? And were do I start?

 

You need to start by figuring out what exactly is happening at the radio when this happens. Is it losing the power or the ground? Without knowing that you are just guessing and wasting your time.

Once you figure out where the problem is at the radio you can start tracing that specific circuit to find the problem.

 

How do I determine if its losing power or the ground

 

You need to look at the wiring diagram. Then using either a multimeter or test light test at each pin that you should have battery + and see if the + disapears or the voltage drastically changes when pressing the brakes. Then do the same checks for the negative connections.

If you find a problem at one of the pins trace the circiut of that specific wire and find what is causing it to change.

 

Well since your still getting sound from your subs, I suspect the radio is fine! I would disconnect the amps and see if the lighting problem corrects itself. It sounds to me that you tapped that circuit for power. I would seperate my stereo stuff from the rest of the car and wire it independantly thru a power relay that works when the car is powered thru the key in both the on and accessory position!