If one could only measure the trials and tribulations of 240 owners and their tail lights over the last forty years, aye... one of life's great imponderables.

In a 1990 Volvo 240DL sedan,
passenger/right side bulb #4 (according to owners manual),
Inner Lower 5W light simply will not come on, leaving the dash bulb failure light illuminated in most cases.

All other lights are functioning correctly.

On the 90, this is the yellow lead in the passenger taillight wiring harness. In years immediately before, that lead was brown. (Appears the two colors were swapped from 89 to 90, at least so far as I have checked.)

Things I have tried (so far):

* Replaced with matching new known-working bulbs on both sides.
* Replaced bulb holder with OEM and after market versions, verified contacts.
* Replaced taillight PCB
* Inspected and replaced all fuses, cleaned contacts in housing with wire brush, checked for bad connections behind.
* Thoroughly inspected contacts and connections in taillight connector, cleaned with wire brush (although not much sign of electrolysis.)
* checked wiring harness all the way back out of the trunk at least;
* Tried two other bulb integrity sensors under the dash, that I pulled from the junk yard.
* inspected back of bulb integrity sensor connector for broken or bad connections.

At this point, I'm really not sure what is left. Any ideas?? This is driving me nuts!

Thanks,
Jameson

 

Are you getting power to the right side tail light? Use a voltmeter and check if power is making it over there. If not, trace back through the different connections till you find power.

If I remember correctly, there are two tail light bulbs - outer and inner. One is a dual filament bulb while the other a single (again I'm going by memory). Are they both not working?