Electrical Issue With Tail Lights
 

My one tail light was out and when I replaced the light bulb it ended up blowing my fuse for my horn and I always needed to push my shift lock in before I could put it in gear so than I ended up just changing the whole wiring harness for that bulb and it works and no fuses are blown but now my parking lights nor tail lights work since Saturday and I've already been pulled over due to this.... please help!!

Re: Electrical Issue With Tail Lights
 

check the bulbs to be sure there good.

after that I would check the connector where the tail light harness plugs into the body harness for power, also check the bulb sockets, (I have a tail light issue but it's the bulb socket itself seems to be a little bit worn inside) and make sure it has a good ground as well.

If that is good, do a voltage drop test on it.

To do a voltage drop test you will need to have the circuit in question powered up (live circuit), your voltmeter on DC VOLTS, and you will check the wires in parallel with the circuit (both leads on the same wire) be sure check all the connectors (one lead on each side) including the bulb socket.

The theory behind this test is the reading on the volt meter should be 0 volts, or less than 0.5V (the lower the better) since all the voltage in the circuit will be used up by the load leaving none left over. Your volt meter can read up to HALF A VOLT and the circuit will be considered "good"

Another thing to keep in mind, is that when doing a voltage drop test any reading you get on your voltmeter is cumulative. I.E. you check the bulb housing and get a reading of 1.5 V, then you check down the wire getting 0, you check the connector and get another reading of 1.5V that means so far in your test, on that 12V circuit, your only getting 9V to the actual tail light.

I hope I explained it good enough for you to understand and if not, you can google "voltage drop test" and there is lots of info on how to do it. hope this helps.