Hello:

93 240 DL Wagon. Indicator lamp on dash came on today suggesting a bad
bulb front or rear. Fronts not likely as I just replaced them.

Checked it out and it was the left rear. Bought a bulb on the way home
so I'd not have to make an extra trip.

No luck. Pulled the bulb socket, cleaned all contacts and then tested
the original bulb (which was fine.)

Next pulled the spade connectors and got out the DVOM.

Voltage at the terminals is .03 volts--which is a LONG way from 12.

Did continuity tests from the fuse block back and fuse is OK and all
else looks good.

I still suspect it's a broken or kinked wire (causing intermittent or
regualr failure) along the line in spite of the successful continuity
test.

Is anyone here aware of this being a common issue?

Any tips appreciated, as I'll not be able to drive at night until it's
repaired and would rather do it myself.

It's a holiday weekend, so if I drive after dark am sure to be stopped
and will get an appearance ticket from the local or State Police. No
fine involved, but will have to take time out to go back to court to
show it has been corrected.

Thanks,

Doc

<doc (AT) nospam (DOT) org> wrote

It's probably a cracked solder joint on one of the circuit boards in the
bulb failure sensor itself, I've encountered this problem several times
recently on various cars.

On Sat, 02 Jul 2005 23:44:49 GMT, "James Sweet"
<jamessweet (AT) hotmail (DOT) com> wrote:


Thanks for the tip! I went up to see a friend today who is an
electronics engineer and has had many older Volvos--but nothing as
recent as this.

He verified what I had already found: lamp socket, lamp and all
grounds were excellent.

We then did a continutity test from the fuse block to the spade clip
that plugs on to the lamp socket and that was also good--so no broken
wire.

I then came up with the idea that we run a bridge wire from the
passenger side lamp terminal to the driver's side.

My buddy Pete did not like that idea much but it worked and I am legal
now.

That said, the indicator lamp on the dash still lights up if headlamps
are on, and that will have to be corrected before the next safety
inspection.

Anyway, my next inspection is due on May 1st 2006, so this buys me
some time in warm weather.


Any tip on where the circuit board is for the bulb sensor failure
lamp? Is it on the back of the instrument cluster? Or is it located
elsewhere?


Thanks Again,

Doc

It's really easy, it's a (usually) red can a bit larger than a D battery
clipped up under the dash on the driver's side above where your left leg
would be. Remove it and the cover pops off. Inside is a stack of 2 or 3
circuit boards, the solder joints will probably look cloudy or cracked on
several of the heavier ones. It'd be wise to check it out soon because if
one cracked more are likely on the way and you could end up with no
taillights at all.