Help! Strange Parking Light Electrical Problem!
 

Here is the problem on my '86 Coupe: When I turn on the parking lights with the headlight switch, only the driver's side front and rear parking lights come on. Nothing on the passenger side. If I turn the headlights all the way on, still nothing. The turn signals on both sides work and with the ignition and headlight switch off, but using the right turn signal, I get the passenger side parking lights to come on as they should. The fuse is good (even replaced it), connections are all clean, but here is where things get strange. Testing the hot side of the incoming wire to the fuse block for the passenger side parking light I only show 11.5 volts. All other hot sides show 12.5 with the car not running. If I touch the wire from the other side of the parking light fuse to the hot side, voltage drops to zero! I also tried connecting the wire to another fuse and still no parking lights. Any suggestions?



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Kurt V
'86 Coupe, '72 MGB, '58 Sprite
Jefferson City, Missouri

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Its a little known fact, that the 86 Carrera (and only the 86) has a weird diode in the right hand parking light circuit!

It is located under the dash, kind of behind the ignition switch.

You can easily locate it, just look under there, you'll see a 3 inch, white holder in the wiring that holds the diode.

Yours has gone bad. Replace it and your problem will be solved.

Call a dealer, they can look up the part number for you. Its around $15-20, as I recall.

Jim T, you and Brian K on the Renlist Board both identified the problem! Fortunately my diode is still ok, however the connections on it were corroded. Cleaned them up and everything is working great! Thanks for saving me hours of tracing wires and connections! I was starting to wonder if this was some bizarre problem that no one had ever seen before. I should have know better:)

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Parking Light
 

My '86 is doing the same thing; all grounds checked are ok. Could I eliminate the diode holder and just splice the two in and one out together? What's the diodes purpose?
Any help is greatly appreciated!

a diode is a directional current flow device,....replace it. They're super frikin' cheap....at least for this 12 volt circuit. A Radio Shack device!


BEST!

Doyle

Talked with my EE friend and his explaination is the diode was put in as a patch to cure a flickering parking light. In '87 the diode wasn't necessary due to an upgraded headlight switch. :rolleyes: