Author Topic: Turn signal problem (Read 14573 times)

sports.racer · « **Reply #15 on:** May 30, 2009, 04:00:29 PM »

This is the circuit for the turn signals, notice that the parking light and the turn signal share the ground at pin 1 of the light assembly.

Normally, this is how current flows through the turn signal circuit.

If you lose the ground at pin 1 however, current will flow through the park lamp...

and find it's way into the park circuit where it finds a ground at the side marker light and the tail light. These lights may all be on dim but they'll all be on. Note that I erased the ground wire in this picture.

bwawuz02 · « **Reply #16 on:** May 09, 2010, 02:17:19 AM »

Any fixes to this gremlin? as it is haunting me too

Who can tell me how to check each ground of this system with a multi-meter to find the bad connection?

I have the diagram and see that G104 looks to be the main under hood ground, so my guess is that it is most likely one of the connectors.

DesktopDave · « **Reply #17 on:** May 09, 2010, 09:11:02 AM »

If you have the bulb always on trouble, I'd start by pulling the bulb and test the positive socket wire for continuity to any solid chassis ground. I'd use the one inside the front left quarter.

If you have the light-out problem like I did, pull the bulb and test the ground wire to a good ground or check for good gaskets. I had a bad side marker that caused the problem. They both do the turn signal, so it took me a bit longer to track it down...both have to be tested. The side markers are a pretty bad design...the bulb overheats the plastic case, cracking it. Water gets in and then shorts the bulb, corroding the socket and (in my case) shorting the front bulb. The front socket and bulb were perfectly OK.

Happily, the socket can be replaced by itself, no splicing required. I also used a bit of silicone to seal a crack & swapped sides so the sealed crack was down instead of up.

bwawuz02 · « **Reply #18 on:** May 10, 2010, 04:08:51 PM »

my problem is as stated above....

turn signals and hazards work when the parking lights are not on, rear parking lights flashing with the turn signals. when i turn the parking lights on, the green arrows on the dash get half dim and the rear turn signals light up with the parking lights; turn signals/hazards no longer flash.

Quote

I'd start by pulling the bulb and test the positive socket wire for continuity to any solid chassis ground. I'd use the one inside the front left quarter.

i would really appreciate it if you could explain this as though i had absolutely no experience with a multi-meter or accessing said location.

DesktopDave · « **Reply #19 on:** May 10, 2010, 04:24:07 PM »

Part I, getting that darn bulb out:

To get at the front bulb, unscrew the lens, remove it & twist the bulb out. The other side marker bulb is in the side of the bumper trim. Use a screwdriver to push the entire lens back and pry it out carefully. Twist the rubber socket and pull it out to get to the bulb. It's a wedge base, just pulls straight out. Check for any troubles with water or cracked sockets before testing...those side markers routinely crack and fill with water. I've had a few that the bulb exploded inside too.

DesktopDave · « **Reply #20 on:** May 10, 2010, 04:31:49 PM »

Part II, using a multimeter:

It's pretty easy. I'll start simple, just ignore this if it's familiar.

Continuity is a path that electricity can follow. All parts of the car are wired from the battery, through a fuse most times, then through a switch, relay, etc, then to the thing that does the work, then off to the car chassis somewhere. That last point is called a ground. The other wires are usually called positives or the 'hot' side if it's a live terminal like the starter.

The multimeter will have two probes and a dial or switch to change functions. Most have nine or more tests you can do. I usually only use three functions...Volts DC, Ohms (resistance) and continuity. You might have to switch the probes into different sockets for different tests. Read the instructions, it'll serve you well.

Now that we're over that, you'll want to test five wires. Use the multimeter (hereafter shortened to DMM) in continuity mode to test the ground side of each socket. BMW usually makes their ground wires brown. Other cars use black or green. Touch one probe to each socket wire, hold the other end to a bit of unpainted metal under the hood. There's a ground strap under the hood that's good for this. You should get continuity from the ground side and no continuity (or infinite) from the positive side. The front signal has three to test...one ground (the shell of the socket), the parking light terminal and the turn signal terminal.

bwawuz02 · « **Reply #21 on:** May 10, 2010, 10:07:33 PM »

Awesome, thanks dave...

will test with the DMM ASAP and report

bwawuz02 · « **Reply #22 on:** December 12, 2010, 01:23:21 AM »

I must be doing something wrong... all grounds from socket to chassis seem to be good, which doesn't make sense. I checked continuity from ground socket to chassis on all parking/turn lamps and got .000-.002. However, I found that both my license plate lights are busted and bulbs are missing. I'm gonna grab a bunch of bulbs from pick n pull 2mro and plug everything in and re-test.

With parking/head lights off, left blinks fast and right blinks normal speed; parking lights flash with turn signals.

With parking/head lights on, cluster lights are constantly on (albeit dimly lit) and neither turn signals nor hazards will flash.

DAMN ELECTRICAL BIATCH!!! I haven't had night time turn signals for over a year now, plus I look like a jackass from behind with my turn signals lit at the same time as my parking lights. By the time i get it sorted out I could have easily just re-wired the whole damn thing.

DesktopDave · « **Reply #23 on:** December 12, 2010, 07:50:49 AM »

I finally (?) found what my problem was. The rear turn signal plate was loose. I was on the road and the left signal started fast blinking. I decided that I was going to fix this once & for all. So I left the signal on with the motor running, and as I twisted the release knob off the turn signal rear cover (with the lights inside it), the signal magically started working. I just left it as-is until I dig up a good rear cover. I also noted that some rear turn signals have so much water that they'll short the bulbs in all sorts of fun ways.

I'd guess that you have a short between the marker light circuit and the turn signal's blinker circuit. I'm sure you've tried this, but I'd start by pulling all the marker lights, the rear cover off the left tail light & the front left turn signal. Test each component by plugging them in one at a time with the signal on.

I'd suspect the front harness or the front socket has corrosion that's shorting both circuits, making a bridge between the markers and the blinkers. You could also test the positive marker wire to the positive blinker wire for continuity to track down a wiring short. Having all the markers off might show up the bad connection.

Your marker lights are powering your blinker circuit serially, essentially halving your wattage so the whole blinker circuit turns on but at low power.