Sensor Light Prob/ 740 Estate

Recently bought myself a second hand Volvo 740 Estate. Its a great car and
the room in the back once the rear seats have been lowered is ideal for me
for work.

The only problem i have with the car is that the bulb sensor light lights up
when i either brake or when i have the headlights on. I have checked and
every light is working so why its the bulb sensor light is coming i dont
know.

Any help would be appreciated.

Stephen Cooper

 

The unit functions by seeing differences in resistance (or current
flow) to the lights. if the PO installed brass base bulbs instead of
the chrome "European" spec bulbs it can set the sensor off. Go through
all the bulbs- remove each one and replace the brass ones. Remove each
bulb and clean the contact at the bulbs' bases and cleam the contacts
on teh bulb holders as well.

At the same time be sure that the correct bulbs are installed. For
example, having the wrong size (wattage) bulb in the 3rd brake light
can cause the warning lamp to illuminate when braking.


__ __
Randy & \ \/ /alerie's
\__/olvos
'90 245 Estate - '93 965 Estate
"Shelby" & "Kate"

 

I had a similar problem when I got my '94 940 Estate.

Most of the time the problem was there while I was driving, and not
there whenever I looked for the cause of it.

It turned out that someone had forced a 4/21W bulb into a holder
designed for a 5/21W (the pins on the side are different). After
changing the bulb all was well for a couple of months then the fault
reappeared intermittently. After cleaning the contacts on the bulb
holders and in the rear light assemblies it went away again and hasn't
come back (yet).