Strange electrical problem, license plate light
 

Right side license plate light is out on my 07 328.

New bulb, no love.
Swapped left good light fixture and bulb from other side, Nope
12.4 V on the left good side across Plug terminals
11.4 V on the right bad side across Plug terminals

Got two new BMW fixtures
Left side good of course
Right side no

Measured fixture terminals
No bulb = 11.4 V
With Bulb = 0 V

is the plug bad? or something else

http://forums.pelicanparts.com/uploa...1721400734.jpg



Old originals, lines show check voltage

http://forums.pelicanparts.com/uploa...1721400734.jpg

Bad ground. Sounds like you have a "floating" 12 vdc you can measure, but when put under load it goes to 0 v?

Where are you measuring voltage? On the connector? Or connector pin to a local ground?

Also, measure the bulb resistance in your hand, them compare that to the resistance read on the connector (bulb side) pins.

I think that's correct.

When I put the Fluke probes into connector holes, I measure 11.4

When I plug in the fixture, no bulb and measure across the contacts (pic with red lines), I get 11.4

When I put the bulb in, goes to 0

Check the resistance on the other side of the connector with the bulb in. I wonder if you have a short and the output is being turned off.

After the relay I think there is a connector for the two positive lines feeding the lights, the left side goes through and the right taps into it. Likely a bad connection there. Follow the wires back and see if you find anything.

isn't the left side just 8" away, why not string two new wires from the light that works to the one that doesn't?

All good advice, going out again after work.

the wiring is mostly hidden in the truck lid. I will make a short ground connector from the left to the right.

You need a good concrete chisel .

LOL! You caught me off guard with this one. Thank goodness I wasn't drinking anything.

I can lend you my Hilti TE-80ATC, that should open up body panels pretty quick so you can find the wire.

OK, here's the scoop.

35 ohms across the bad side bulb

Attempted to bridge the ground wire connectors left to right but but my chisel collection was either 7" or closer to 9 so they wouldn't work, classic Goldilocks syndrome, needed 8" (that's what she said). So I made a temporary wire connection across the ground wire terminals, IIRC, grey is ground in German cars. Anyway, that worked perfectly. No need to bridge the brown wires.

I don't like those little clamp on splicers. What would be a good quality or factory way to make that connection permanent?

To answer your last question...19 minutes, well worth it.

https://www.youtube.com/watch?v=E_m8xf3vfYE&ab_channel=IrvinOrtega

Another option:

https://www.youtube.com/watch?v=dImF86OwiK8&ab_channel=electronicsNmore

Dark magic, obviously. Have you pissed off any sorcerers lately?

That's like asking 'what oil should I use, and do I need ZDDP?'.

I always solder, tape, and then shrink wrap. Lots of people say that's a hack and it will fail. It has never failed me. I like to do a good wrap with the two wires, I think there is actually a NASA approved warp if you search.

Butt splices with a proper crimp tool are also good. I like the shrink wrap to hide the mess and keep water out.

I have a soldered and shrink wrapped connection submerged in my pool 24/7 on my robot, it is fine.

Thanks, I have generally soldered and shrinkwrapped too. Ducati headlight last summer. Lot of vibration, still working fine. I like the connections Paul posted too.

http://forums.pelicanparts.com/uploa...1721476866.jpg

That sort of looks like the front of my wife's truck after someone stole the front off it

I always thought solder/shrink wrap was more permanent. Works better than the crimpy way, whether you have the right tool or not, seems to be pretty durable too