They are, but only if hooked up to your car correctly. Make sure it's professionally installed.
Yes, it has to be hooked and used correctly.
You don't say what kind of car so make sure all of the wires were hooked up correctly.
It may be Short Circuiting, or your ground might not be hooked up, or maybe your wires aren't good. (Good meaning not connected correctly or they have been cut)
Car audio connectors may cause sound problems if they are not hooked up correctly. The sound may not be clear or there may be no sound at all. Check the manual which came with the connectors to make sure they are hooked up properly.
First I would check that all the wires are hooked up correctly. Next check the battery cables and the ignition fuse. Next I would check the solenoid. Good luck
You may have a dead battery.
Check the wire to the sensor and be sure it is hooked up. If so remove it from the sending unit. Turn the ignition and have someone watch the gauge while you ground it to the engine. If it moves the sender is bad.
Make sure everything is hooked up then if you have a game put it in and turn it on it should work, if not then you must have not set it up correctly.
Try checking the fuel pressure regulator that's what gives the engine gas and how much its hooked to a vacuum line.
the battery was hooked up incorrectly this was answered by Manager of Auto Zone
well, you make shure they are hooked up.