Upon starting my car the other day I heard a funny squeal coming from my stereo. If I hit the gas I can hear rpms through my car stereo!? Upon further electrical inspection I noticed that neither of my brake lights are working. All the suspect fuses seem to be good and all bulbs are good. I'm sort of at a dead end and was curious if anyone has experienced this before?
-98 discovery

 

I would probably start by checking all your spark plug wires. Make sure they're on snug, and check the shielding for abrasion.

 

The radio issue is probably a ground issue. Don't know on the brake lights. Would check both bulbs, all fuses again, and the brake switch on the floor behind the brake pedal.

 

If it is a constant noise that increases in "speed" with the engine speed then it is a alternator for the stereo RFI.
If it is more of a "popping" noise then it is the plug wires.

Brake light switch on the back of the brake pedal for the other.

To rule out the alt remove the belt, start the engine and listen for the RFI, if it is gone then you know its the alt or a loose wire on the back of the alt.

 

I agree with the above statements but I would suggest starting on the return side, the positive side of all automotive circuits are shielded and protected and usually don't show to many problems, however the negative side is the exposed side and is shared throughout the vehicles chassis. check all your grounds first starting with the battery cable (both sides) and then reinforce the grounds in the kick panels and in the back at the lights. I would say 80% of the time strengthening the grounds will fix your issues.

 

I would suggest you look into grounding on the back of the truck. I was in the middle of replacing my amp, and at one point, it was backfeeding through the stereo with the same whine.

Since your truck is shifting out of park, it isn't the switch. Check the ground to your lights in the back...

 

Good catch. I missed the fact that he is able to shift.

 

Ever come up with anything? I am going through a 98 with the same prob right now...

 

About a month ago I had wired a audio cord to the back of my car stereo for my iPhone. I decided to pull it back out and my squeal all of a sudden stopped!?
As for the no brake light issue I haven't had any luck. Car electrical absolutely boggles my mind and I feel pretty clueless. I do have the single brake light above my back door but that's it, just enough to get by. Does anyone have any particular wire locations I should maybe check out?

 

with your audio problem I am interested in how you wired this audio cord in. basically that I can explain, similar to a magnet next to a tv, the audio path in certain instances (this one actually) is shielded from certain types of radiation, the radiation that I am talking about is emitted from other wires like power and ground wires. my guess is you weakened or damaged one of these shielded cables and in doing so exposed the sensitive audio wires to radiation (or possibly directly entered it into the path with this cable you put in) thus presenting itself, unlike the discoloration on a tv from a magnet, RF interference in an audio signal is displayed by noise.

as for your brake light issue, there is if I remember correctly a connector near the passenger side alpine window that has the brake wiring in it. this should not have any problems but it may be some where to check. otherwise the rave manual has schematics of the brake light wiring, and when you follow the schematics there are connectors shown that are displayed with a number, then also in the rave manual is a picture of each connector with its location, as well as a pin out diagram with the wire colors in it. you can tie all of this together to get a pretty good idea of the wiring route, then just take a multimeter and trace the circuit back until the power goes away, or try starting at the back and work up until you find power in the circuit. working backwards will show if the problem is a bad ground at the light housing, this is probably the most likely problem since your third brake light works. the connector I explained by the alpine window is the connector where the upper and lower brake lights separate.