Passenger side position lamp fault.

[Nathan Buffery]

As the title suggests, I have a fault with my passenger side side lights on my 2013 focus estate.

A couple of days ago a motorcyclist who pulled in behind me told me my rear side lights, on the passenger side, were flickering. When I pulled up behind a car I could see the front passenger side was doing the same in the reflection. Since then they do not come on when I put the lights on. 

Here's the strange thing.....when I unlock the car, the pasenger side lights come on briefly (all front and both rear). The drivers side stay on. 

Forscan are giving me the following codes:

B1098 left position light- circuit short or open.

Before I start putting my back out trying to get to the connections on the BCM, is there anything obvious I could try? 

Thanks in advance.

 

[F0CUE]

5 hours ago, Nathan Buffery said:

As the title suggests, I have a fault with my passenger side side lights on my 2013 focus estate.

A couple of days ago a motorcyclist who pulled in behind me told me my rear side lights, on the passenger side, were flickering. When I pulled up behind a car I could see the front passenger side was doing the same in the reflection. Since then they do not come on when I put the lights on. 

Here's the strange thing.....when I unlock the car, the pasenger side lights come on briefly (all front and both rear). The drivers side stay on. 

Forscan are giving me the following codes:

B1098 left position light- circuit short or open.

Before I start putting my back out trying to get to the connections on the BCM, is there anything obvious I could try? 

Thanks in advance.

 

I would check the BCM connections are not corroded as water from the washer resorvoir can leak and track down to the BCM.

[Nathan Buffery]

6 hours ago, F0CUE said:

I would check the BCM connections are not corroded as water from the washer resorvoir can leak and track down to the BCM.

Thanks Ian. I have checked this previously when I saw your post about it and there are no signs corrosion on any of the connections or pins. 

I'm now wondering if somewhere on that circuit the wire is earthing out, but not enough to blow the fuse. 

[Nathan Buffery]

I don't suppose anyone has an easier way of identifying the number for the connections on the BCM. When I look on the wiring diagram I can see that its pin 1 on connection 2, but when I'm upside down in the passenger seat with a torch and blood is rushing to my head, all i can see is the names of the colour on the BCM. 

[Nathan Buffery]

So as I have already stated, passenger side side lights front and rear were coming on briefly when I unlocked the car, but wouldn't come on after that. DTC was giving position light short circuit. 

My initial thoughts were a loose connection on the BCM, especially as it had been flickering.  I went through the wiring diagram and identified the feed to the rear position lights. I unpinned the feed and put another pin in which was connected to my test light. Test light and front position light came on, so it was a problem with the rear. 

My next thought was the connection going through to the tailgate, as I have had problems before on my previous focus. So I found the connection going up to the tailgate and unplugged this....no different.  

So my next suspicion was a break or shorting of the wire from the BCM to the rear. Passenger seat out, all the trims off and the carpet pulled back. No signs of any damage to the loom. 

After a bit of head scratching I decided to look at the rear light cluster. I took it out and unplugged the bulb. Lights stayed on. Swapped the bulb with the driver side one. And the driver side did the same. I measured the resistance on the bulb and it was all over the place, so it was a faulty bulb!! 

What threw me was the fact that the bulb came on when I unlocked the car. So the moral of the story is to check the simple things before you start ripping the car apart!!! 

[unofix]

Hi Nathan, its a pity I missed your original post or I would have suggested checking the Tail/Stop Light bulb. Sometimes with these dual element bulbs when one element fails it falls on to the other element causing a short between the taillight and brakelight circuits with interesting results.

The good news is you found it and have fixed the problem.

[Nathan Buffery]

1 hour ago, unofix said:

Hi Nathan, its a pity I missed your original post or I would have suggested checking the Tail/Stop Light bulb. Sometimes with these dual element bulbs when one element fails it falls on to the other element causing a short between the taillight and brakelight circuits with interesting results.

The funny thing is, the bulb looked perfect with no blacking on the glass and the elements looked in good condition. Perversely, the drivers side looked in terrible condition. I'm just glad I got ot sorted as I was beginning to think it was a faulty BCM.

[SMAX2011]

2011 Smax.  In case anyone needs info, I found this chat while searching for a solution to the same issue.  "position lights bulb fault".  Fault was on the OS side (drivers side).

I found that the issue was down to a bad earth. A simple scan with Forscan provided the code.

My issue was with the tailgate light cluster. The threaded pins that pass through the metal panel of the tailgate had rubbed some for pain away allowing for the pins to short on the body of the door.  A quick touch up with a pen stick, and then reassemble everything solved the problem.