I realize this isn't an E30, but I'm having no luck finding information on other forums so I'm trying to branch out in the hopes someone can help me.
We found that the headlight switch in my E28 had melted pins relating to the left side of the car. When I bought the car the PO had wired in Euro low beams and not used heat shrink so the connectors were corroded.
We cut the wires back and replaced the connectors with BMW spec clips and heat shrinked them up. The left low beam still would not work. Through 4 hours of diagnosis we found what I can only describe as black magic witchery.
Here are the details:
- First off, the voltage in the images is low because we were testing this all day and the car's down for a new oil pan so we couldn't run it.
The battery was reading 7.5V.
At the current 7.5V the passenger side headlight is lit. The drivers side is not.
The power wire to the drivers headlight reads 7.33V when disconnected.
Resistance at the same wire is 1.2O
When the wire is connected to the headlight, suddenly there is no voltage.
We tested the above with the headlight wiring ground connected, and then again running our own ground to the frame and got the same results. No voltage at the power wire when connected.
When we run power directly from the battery to the headlight terminal, the light is illuminated.
This works with both the headlight wiring ground connected and with our own ground to the frame.
I don't understand why the power line to the headlight would HAVE POWER when disconnected, then suddenly have no power when connected.
We swapped bulbs from side to side. We swapped headlight buckets side to side. Everything works on the passengers side but not the drivers side.
Someone tell me how this is possible.
We found that the headlight switch in my E28 had melted pins relating to the left side of the car. When I bought the car the PO had wired in Euro low beams and not used heat shrink so the connectors were corroded.
We cut the wires back and replaced the connectors with BMW spec clips and heat shrinked them up. The left low beam still would not work. Through 4 hours of diagnosis we found what I can only describe as black magic witchery.
Here are the details:
- First off, the voltage in the images is low because we were testing this all day and the car's down for a new oil pan so we couldn't run it.
The battery was reading 7.5V.
At the current 7.5V the passenger side headlight is lit. The drivers side is not.
The power wire to the drivers headlight reads 7.33V when disconnected.
Resistance at the same wire is 1.2O
When the wire is connected to the headlight, suddenly there is no voltage.
We tested the above with the headlight wiring ground connected, and then again running our own ground to the frame and got the same results. No voltage at the power wire when connected.
When we run power directly from the battery to the headlight terminal, the light is illuminated.
This works with both the headlight wiring ground connected and with our own ground to the frame.
I don't understand why the power line to the headlight would HAVE POWER when disconnected, then suddenly have no power when connected.
We swapped bulbs from side to side. We swapped headlight buckets side to side. Everything works on the passengers side but not the drivers side.
Someone tell me how this is possible.
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