map light / dome light issue

[Scomell]

Hello,

Thank you for your thoughts.  

 

Here is my problem... the dome and map light aren't working.  bulbs are good.  When I put a probe to the map light harness it tells me that one feed is connected to positive and one connected to negative , but I get no voltage.  For the dome light, the probe is telling me that all the wires are a negative feed.  that really shouldn't be that way.  

 

Any thoughts would be greatly appreciated.  

 

It's a late 260Z automatic.  

 

Doesn't everyone love electrical issues .

 

Thank you,

Scott

Edited July 6, 2015 by Scomell

[Zed Head]

one feed is connected to positive and one connected to negative , but I get no voltage. 

 

This statement is illogical.  Literally.  "Positive" means the battery's positive post and "negative" means the negative post.  The only way you'll get no voltage is if the battery is completely discharged.

[Scomell]

Yes... that is why it is all so strange.  I would expect to see voltage as well.  but when i measure the voltage with the key on, I get none.  the continuity of the wire is one negative and one positive.  no reason why the light shouldn't turn on.  I even took it out and supplied 12 volts and it worked.  wondering if there is a relay or something that could be bad.  

 

thanks,

-S

[Kurbycar32]

I have an early 260z and there are no relays between the dome light and power.  You likely have a problem with the fuse or wiring.  Remove the light fixture and test for power behind it.  If you have power your fixture needs attention or replacing.  If you do not have power do a continuity test on each side of the circuit to determine if you have a wire fault.  My money is on a bad fixture, and that you can probably clean the electrical switch to get it working again.

[Zed Head]

Scomell, you might be mixing up your terms.  Maybe you meant the light doesn't light even though there is voltage present.  That's different than there's no voltage with the light installed.  You'll still see voltage with high resistance in the circuit.  High resistance won't let enough current flow to let the filament glow.  Kurby's dirty switch or connections are likely.

[Scomell]

thank you for your replies..  

 

being a newby to the Z world... can you give me a heads up on what the "Kurby's dirty switch" is.  

 

thanks!!

[Zed Head]

Referring to Kurbycar32's comment.  The switch at the map light itself.  

 

If you want to test the wiring supplying power, take a light bulb and attach a wire from the positive feed to one electrode and ground the other. Easiest with a spare light bulb fixture.

[Kurbycar32]

Im trademarking "Kurby's dirty switch"

 

I took this image of a dome light shamelessly from the internet.  You can see the whole circuit is exposed metal, and I bet yours looks gross.  Make sure every metal-on-metal connection is nice and clean and then rough it up a bit with an emery board (use an old fingernail file).  you may even need to bend those contacts a bit so they have a nice tight connection.  The rotating map light is the same idea but i couldn't find a good picture, just refresh all of the contacts.  My experience is that almost everything on these cars can be stripped, cleaned, reassembled and brought back to life without buying new stuff.

Edited July 6, 2015 by Kurbycar32

[Scomell]

Zed Head and Kurbycar32,

 

Thanks for your help and time.  Did what you said and got them working.  

 

If you make "Kurby's dirty switch" T-Shirts, I'm down for one.

 

Best,

Scott

[Captain Obvious]

If you make "Kurby's dirty switch" T-Shirts, I'm down for one.

 

Me too!

 

[Mikes Z car]

The dome light on my car came to life when I cleaned the two door jamb switches.  I pried both out and scraped the metal on the car frame and on the switch.

[Scomell]

well... guess what?  now they aren't working again.  I noticed that the after market radio has stopped as well.  I looks as if it's getting the constant from the battery but not the signal from the ignition to turn fully on.  I can crank the car so that switch is working. and if I turn on the lights, the glove box light works (just an fyi).  I didn't do anything to the car since the map light and dome light stopped were working.  I'll try what "Walmart Greeter" suggested.  could there be a relay that is bad or intermittent?  

 

Thanks everyone.

 

ugh...

 

-Scott