Got an odd one for you. When I get above 70 mph, I sometimes get a rear bulb failure on the left turn signal only when passing vehicles. The bulbs are new, the tension and connection to the bulb is good. I was thinking vibration but the bulb is tight. Anyone else ever run in to this? Possible ground issue?
Thoughts?

Thanks,
Scott

 

If you haven't done so, clean and burnish the bulb sockets as a first step....

 

Unplug the wire socket and exam the condition of the connectors. They are EL shaped blades pointed at each other. See if any are out of alignment. If they are you can press from the outer edge and re-position them. Also check the ground connector and see if it is distorted or charred from heat. There are numerous posts about adding an additional ground wire. Inadequate ground is a common problem. It is easily overcome by adding and additional ground wire from the chassis to the light fixture.
Also you may want to remove and clean the SCLM connector. It is located underneath the fuse panel in the battery compartment.
One last thing to check is that when it happens engage the cruise control. If you get the warning cruise not available it would indicate the brake switch is causing the problem

 

When this happens does the flasher indicator blink faster? My car has never said which bulb is faulty, it just says rear bulb failure. Is cruise control on when this occurs? I would start by looking at every socket on the left side for corrosion, misalined contacts and mismatched brands of bulbs left vs right.

 

That was the first thing I did when I put new bulbs in. They appeared to be clean but I'll check again when I pull the left tail light assembly out.
Thanks!

 

I'll look at that, too when I pull the assembly out. Don't believe that it is cruise control related as I very rarely use the cruise and will sometimes do it when I'm accelerating to pass someone. I saw the post about adding ground wires (by the way, whoever posted that, nice photos) and I'll probably try that, too.

 

Cruise is not on when this happens and I always replace bulbs on both sides with matched bulbs whenever one fails. learned that one back in my Volvo days. The bulb failure light on the old 240's was really sensitive to mismatched bulbs. What's odd is that this little issue does seem to be speed related though...

The speed of the turn indicator does not change when the bulb failure warning flashes.

And, looks like winter is rearing its ugly head here in western Michigan. Time to plug in the battery tender and put the car up waiting on the return of nicer weather. I'm going to pull the assembly and check for all the suggested ideas plus add grounds to both sides.

Thanks!

 

So, last May, I finally figured out what was happening. Over the winter, I incorporated the extra ground wire, no luck. Cleaned/polished all the bulb socket connection points, no luck. Checked all the ground points and connectors I could find on the assembly and wiring harness. Even went so far as to pull out my trusty VOM and checked the resistance on the diodes controlling the feedback to the circuits, all good. And, when putting everything back together yet one more time, I again thought about the suggestion from AVERN1. Pulled the connector apart one more time, took a bright light and CLOSELY inspected the pins. The number one male pin on the wiring harness to the left rear tail light assembly had a very slight twist to it (missed this the first time I checked them). Took out a very small needle nose plier, straightened and re-aligned the pin inside the connector, put everything back together, hit the interstate guess what.... Everything worked correctly. Turn signal worked at low speed, high speed and everywhere in between. Only thing I can think of is that at low speed, the connector pin made good contact with the female side, when I hit 70 mph and above, the road vibration caused the pin to have an intermittent contact making the bulb failure light come on. So, thank you Vern! It was the connector pin.

 

I've also had this connector pin issue on the left side. Mine was intermittent, but not speed dependent. I thought it was just my car Thanks for posting this.

 

Thanks, folks. I've been dealing with a similar 'cruise/rear light' issue. Most of my tests are indicating a brake switch acting up.
Also, vibration over 70 may be another concern.
Just a thought.

Jip

 

Which part of Michigan? I'm a bit East of Grand Rapids.