Phantom electrical issue


#1

I have a 2003 Olds Silhouette. Various electrical bits have stopped working: first the passenger seat warmer, then the built-in air pump, the cruise control, both rear brake lights (more about that in a sec) and the traction control works some days, not others. Throwing a meter on the bulb sockets for the rear brakes, I get no current. putting the meter on the wires to the light assembly, I get current. I find it very odd that both brake light sockets went simultaneously. I’ve checked all the fuses - they’re good. Has anyone encountered this kind of behavior?


#2

Never encountered this… all the systems you mention seem unrelated - the only thing common would be the ground. It is unlikely that both brake light sockets would fail at the same time - BUT did they fail at the same time or did you just notice them at the same time?


#3

First, you are not measuring current, you are measuring voltage. Second, it is sometimes difficult to measure voltage in sockets. you have to get the probe in just the right place. The small contact at the bottom of the socket has the voltage. The area around the contact is insulated, the sides should be the ground. What you do to measure the voltage is carefully put one probe against the contact point, then touch the other probe to the side of the socket. If you are sure you are not getting any voltage there, then instead of touching the side of the socket find another place to touch ground on the car body. If you are now reading voltage then you need to check the ground on the sockets. And losing ground from time to time does happen. It might be, if the socket is the kind that unplugs from the housing, that it just isn’t making good contact. Or you may need to replace the socket. Also, do not rule out an open wire in the system, allowing only a small amount of current to get through, even though the meter reads 12 volts.


#4

go back and read ohms LAW, you know E I R. YOURE INCORRECT on the assumption.


#5

You stated that you have no voltage at the sockets but you do on the wires, at some point at least, for the brake lights. This means there is an open connection between those points somewhere.

The cruise control problem may be related to the brake light problem but check the switches on the brake pedal to see if they are working as they should be.

To help you fix these problems I recommend you purchase a factory service manual to help you track down the troubles. There isn’t anything better than having a manual to help you fix these things.