Help with electrical problem (rear lights)

[dosh8er]

I have a friend w/ an 87ish civic.. (I know.. not an accord)

When the car's rear tail lights are on (brakes, turn signal, etc.) they work fine.. but when the lights are turned ON (as in the Headlamps or the running lights), these lights fail to work..

Could someone suggest some ideas?I haven't looked at it too much yet, but any hints or advice is welcome.

[Dutchboy]

it could be the bulb...or the fuses...

the bulbs use a double fillament in them so if the fillament for the runnning lights burns then they obviosly wont work and the brakes could depending on the bulb of course...

i think are cars use this setup at least...ive never had to replace one so im going by other cars setup.....quick test is to replace with a new bulb and see...
or make sure all fuses are good.

BEn