Short-lived brake light bulbs on a 740 estate?

[Andy Dingley]

Why am I forever changing lightbulbs in this thing? Just the rear side
brakelights, never anything else. Decent quality bulbs, of numerous
different brands, yet they keep snapping the filament (no
discolouration). Is there some sort of vibration problem or cold
draught problem with the lamp holders? Anyone else having the same
problem?

 

[c.fiedler]

Why am I forever changing lightbulbs in this thing? Just the rear side
brakelights, never anything else. Decent quality bulbs, of numerous
different brands, yet they keep snapping the filament (no
discolouration). Is there some sort of vibration problem or cold
draught problem with the lamp holders? Anyone else having the same
problem?

My 97 850 wagon has the same problem. Generally the left brake light.
Have changed the holder thingy once with the same problem.

Chuck Fiedler
Nothing but Volvo for 32 years now

 

[James Sweet]

Why am I forever changing lightbulbs in this thing? Just the rear side
brakelights, never anything else. Decent quality bulbs, of numerous
different brands, yet they keep snapping the filament (no
discolouration). Is there some sort of vibration problem or cold
draught problem with the lamp holders? Anyone else having the same
problem?

Sure they're the right bulbs? Have you measured the voltage with the
engine running to see if it's a bit high?

 

[Michael Pardee]

Why am I forever changing lightbulbs in this thing? Just the rear side
brakelights, never anything else. Decent quality bulbs, of numerous
different brands, yet they keep snapping the filament (no
discolouration). Is there some sort of vibration problem or cold
draught problem with the lamp holders? Anyone else having the same
problem?

Our 765T does not consume brake light bulbs. It's only the brake filaments
and not the tail light filaments?

Mike

 

[Roadie]

Why am I forever changing lightbulbs in this thing? Just the rear side
brakelights, never anything else. Decent quality bulbs, of numerous
different brands, yet they keep snapping the filament (no
discolouration). Is there some sort of vibration problem or cold
draught problem with the lamp holders? Anyone else having the same
problem?

From a former 740 owner look for the following:

Corroded contacts in the light socket.
A buildup of water inside the lens when it rains. It took for ever to
figure this one out. The inexpensive solution is to drill tiny holes
at the bottom of the lens to keep water from building up.

 

[John Horner]

Why am I forever changing lightbulbs in this thing? Just the rear side
brakelights, never anything else. Decent quality bulbs, of numerous
different brands, yet they keep snapping the filament (no
discolouration). Is there some sort of vibration problem or cold
draught problem with the lamp holders? Anyone else having the same
problem?

Generally high contact resistance somewhere in the circuit. Start by
cleaning the contacts which the bulb sits on. There can also be
problems in the taillight circuit board or elsewhere. Somewhere you
have a place where contact is being made intermittently.

John

 

[Josh]

Generally high contact resistance somewhere in the circuit. Start by
cleaning the contacts which the bulb sits on. There can also be
problems in the taillight circuit board or elsewhere. Somewhere you
have a place where contact is being made intermittently.

John

I had the same problem in my '83 240. I cleaned and reseated all the
bulb holders, even bending the pins a little to make better contact and
the problem left immediately. Sometimes the contacts corrode and need
a very light sanding to improve contact area