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Posted by: RobW Aug 22 2015, 08:34 AM

I'm getting 5-6 volts at the interior light. That can't be right can it?

Any ideas on how to get it up to 12?

Posted by: RobW Aug 22 2015, 08:55 AM

Going for a ride...


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Posted by: Spoke Aug 22 2015, 08:59 AM

Are you getting 6V at the light contacts with the bulb on or at the spade connectors to the light fixture?

Check and clean all contacts. If you have 6V at the spade connectors to the light fixture, the issue may be the door switch.

Do you get the 6V with the switch on the fixture set to ON and with the door open?

Posted by: RobW Aug 22 2015, 09:03 AM

Thanks. I got 6 volts connecting the spade to the ground bypassing the bulb and assembly. Where is the switch located?

Posted by: rhodyguy Aug 22 2015, 10:21 AM

on the front of the door jam. near the color tag.

Posted by: Spoke Aug 22 2015, 11:26 AM

If I'm not mistaken, The wires at the door switch are always hot. You may want to disconnect the battery negative before pulling the switch out. Pull the switch out to test then reconnect the battery.

Posted by: Dave_Darling Aug 22 2015, 12:17 PM

The door switch wires are not always hot. They can be, if you have the light switched to the "on when door open" setting.

Rob, I can't picture what you were measuring. Please describe in more detail?

There is a black/red wire that is always hot going to the interior light. There is a brown wire that is always grounded. There is also a brown/white wire that is grounded when either door is open, because it goes to both door switches.

Did you unplug the black/red wire and measure to a known good ground? The battery post would be ideal, but some bare chassis metal will work. That is measuring just the path to get the power in to the light. If you measured 6V there, you have some very dirty connections or other high-resistance things going on with that power path.

Measuring between the black/red wire and the brown wire tests the whole circuit for the light. (Unplug the wires from the light to do this test; if you leave them plugged in you can get odd readings. Or at least remove the bulb so you don't have a direct path from + to ground through the bulb.) Getting 6V here, if you got 12V on the earlier measurement, means the ground path is messed up. Some high resistance connection, or going through some other component--light, motor, resistor, something.

Repeat the test with the brown/white wire with each door open. Again, if this is 6V and the others were 12V, there is a lot of resistance in the circuit. The switch for the open door is the primary suspect at this point.

You can also use the ohmmeter function on your multimeter to see what kind of resistance you get from the brown and brown/white wires to a good ground. Should be very low.

My first guess is that your measurement was actually the voltage dropped by the bulb, and that everything is OK. But I could be wrong.

--DD

Posted by: RobW Aug 22 2015, 12:54 PM

Dave,

You're right again. Got better voltage.


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Posted by: RobW Aug 22 2015, 12:55 PM

And then


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Posted by: RobW Aug 22 2015, 12:56 PM

And success!


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Posted by: mepstein Aug 22 2015, 01:02 PM

I switched mine over to an led bulb. Pricey but it stays cool to the touch.

Posted by: RobW Aug 22 2015, 09:39 PM

You got that right. This thing doubles as a heater!

Posted by: Mike Bellis Aug 22 2015, 10:10 PM

Not exactly hot. It's an open ground. When the switch is out of the car, the potential on the brown/white wire is about 12V+. This is only due to the open circuit voltage. The brown/white wire is a switched ground. Most wires with a white stripe (European cars) are switched. The main color will tell you the function; brown or ground in this case.

If these wires were truly "hot", they would blow the fuse when installed as the switch shunts to ground.

Posted by: Mblizzard Aug 23 2015, 03:56 AM

I got tired of the poor light and heat so I installed a strip of side emitting LEDs just below the back pad. About $15. Lots of light. No heat!