Tail Light Lenses Melt - 940 Wagon

  • Thread starter Thread starter thunderbeast
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thunderbeast

Does anyone else have this problem?

My 1994 940 Wagon has issues with the tail light lens assemblies. It
appears that the heat from the bulbs melts the plastic and causes the metal
contacts to receed. This causes the assembly to lose contact witht he bulb
holder assembly, and the lamp does not get DC power. The red film lens
coloration is gone on one side (burned off?), and the socket is completely
melted and distorted.

I have had this problem with assemblies on both sides of the car. I am
using aftermarket parts for replacements, but wonder if this is a known
problem with this model. Are the original equipment fabrications any more
reliable? At $250US each (as opposed to $54 for the aftermarket versions),
I hesitate to buy them instead.

DK in Oregon
 
I am wondering if you are using over-wattage bulbs in there. It shouldn't
happen.

RS
 
thunderbeast said:
Does anyone else have this problem?

My 1994 940 Wagon has issues with the tail light lens assemblies. It
appears that the heat from the bulbs melts the plastic and causes the metal
contacts to receed. This causes the assembly to lose contact witht he bulb
holder assembly, and the lamp does not get DC power. The red film lens
coloration is gone on one side (burned off?), and the socket is completely
melted and distorted.

I have had this problem with assemblies on both sides of the car. I am
using aftermarket parts for replacements, but wonder if this is a known
problem with this model. Are the original equipment fabrications any more
reliable? At $250US each (as opposed to $54 for the aftermarket versions),
I hesitate to buy them instead.

DK in Oregon
Click to expand...
A bad contact between the bulb-holder and the lamp housing might cause
enough heat for the plastic around the contacts to melt. This might be
more likely in cheaper aftermarket housings than in original higher
quality Volvo parts. If the red coloration is being burned off it must
only be on the surface of the lens, rather than right through the
plastic. Possibly the additional heat from the bad contact, or gases
from the melting/burning plastic, are destroying the coating.

My '94 940 wagon has an intermittent bad contact problem but it's only
on a brake light so it wouldn't generate as much heat as it would if it
was on a tail light.

You might be better off buying used original parts from a breaker, or
off eBay, than repeatedly spending money on cheap aftermarket new parts.
 
Rusty said:
I am wondering if you are using over-wattage bulbs in there. It shouldn't
happen.

RS
Click to expand...

Certain aftermarket taillights for the 200 and 700/900 wagons seem to be
made of plastic that's not heat resistant enough. Maybe if you mounted
a 12 volt computer fan to air cool them.... ;)

--
Mike F.
Thornhill (near Toronto), Ont.

Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)
 
A bad contact between the bulb-holder and the lamp housing might cause
enough heat for the plastic around the contacts to melt. This might be
more likely in cheaper aftermarket housings than in original higher
quality Volvo parts. If the red coloration is being burned off it must
only be on the surface of the lens, rather than right through the
plastic. Possibly the additional heat from the bad contact, or gases
from the melting/burning plastic, are destroying the coating.

My '94 940 wagon has an intermittent bad contact problem but it's only
on a brake light so it wouldn't generate as much heat as it would if it
was on a tail light.
Click to expand...

Wouldn't that trip the bulb failure light?


Regards,

Boris Mohar

Got Knock? - see:
Viatrack Printed Circuit Designs (among other things) http://www.viatrack.ca

void _-void-_ in the obvious place
 
Boris said:
Wouldn't that trip the bulb failure light?
Click to expand...

I don't know what point the bulb failure light starts tripping. After
cleaning up the contacts the bulb failure light stays off for about a
month but I don't know if the contact is as good as it should be and I
don't know whether or not the contacts are getting hot. Eventually the
bulb failure light starts coming on intermittently and, now, I know it's
time to do another clean-up.

At first I had a lot of trouble diagnosing the problem because the bulb
failure light would only come on while the car was moving. If I parked
up to take a look at what was happening everything worked ok! Finally
the contact became poor enough for the bulb failure light to come on
while the car was standing still.

While trying to figure out the problem I was followed by more cops than
in the previous 28 years of driving (or it just felt that way). :)
 
My '94 940 wagon has an intermittent bad contact problem but it's only
on a brake light so it wouldn't generate as much heat as it would if it
was on a tail light.

You might be better off buying used original parts from a breaker, or
off eBay, than repeatedly spending money on cheap aftermarket new parts.
Click to expand...



It's worth looking, though my experience has been that taillights are
almost always either the first thing to go at wrecking yards or they're
in bad shape. A higher class more expensive yard might have better stuff
of that sort though.
 
James said:
It's worth looking, though my experience has been that taillights are
almost always either the first thing to go at wrecking yards or they're
in bad shape. A higher class more expensive yard might have better stuff
of that sort though.
Click to expand...

Check the reversing light lenses carefully. As posted in another recent
thread the solvent welds do sometimes fail.
 
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