Insufficient voltage on side marker light.
08-25-2017, 06:07 PM
#1
Drifting
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Insufficient voltage on side marker light.
My left rear side marker light won't work. I've pulled the marker and tested the bulb and bulb socket successfully. I tested the wiring and got <5v on that side, compared to 8v on the passenger side. What could be the cause of the lower voltage? Bad wiring and I just need to trace it back until I find better voltage somewhere and replace from that point back, or????
08-25-2017, 07:31 PM
#2
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Clean the two 2-pin connectors in the hatch area. They commonly get green with corrosion.
08-26-2017, 01:49 AM
#5
Electron Wrangler
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Neither side is very good.
If you measure at the bulb socket only - you have no idea where the losses are.
So measure bulb center connection to Battery +ve and see what voltage is dropped on the supply side, then measure bulb ground to Battery Ground (-ve) and see what voltage is dropped there. You need to do this with the bulb still in the circuit or it will be meaningless (so figure out how to do that).
If you have voltage drop on the ground side clean the cluster connector and the ground points. If you have voltage drop on the supply side check all the supply side connections (fuse, bulb controller, in line connectors and cluster connector.
Obviously you may also have both.
Alan
If you measure at the bulb socket only - you have no idea where the losses are.
So measure bulb center connection to Battery +ve and see what voltage is dropped on the supply side, then measure bulb ground to Battery Ground (-ve) and see what voltage is dropped there. You need to do this with the bulb still in the circuit or it will be meaningless (so figure out how to do that).
If you have voltage drop on the ground side clean the cluster connector and the ground points. If you have voltage drop on the supply side check all the supply side connections (fuse, bulb controller, in line connectors and cluster connector.
Obviously you may also have both.
Alan
08-26-2017, 09:46 AM
#6
Racer
Wally had a write up on cleaning all the grounds all over the car. Took some time to do, but after it was done a few of my electrical issues went away. Not saying that's the cause here, but well worth the efforts and peace of mind knowing the grounds are all good.
08-26-2017, 05:12 PM
#7
Chronic Tool Dropper
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928 Specialists site used to host Wally Plumley's "Annual Electrical Maintenance" instruction. It was no longer there a month or two ago when I went to link it in another thread, but I have a copy archived somewhere. In it, Wally covers ground points and connection cleaning. The marker light sockets usually need a bit of extra attention since they are regularly exposed to water and everything else the tires roll through. A small pipe-fitting cleaning brush helps get crud out where the bulb lives. I usually add a smear of Vaseline in the socket after everything is clean again, to try and at least slow down the corrosion.