190e, roof warning lights stay on !

[longlostpoet]

my 1991, 190e has developed a fault which i can't seem to correct.
in the roof, below the front interior light, is the seat belt warning light cluster.
these RED lights are now on all the time !
even with the key out of ignition & doors locked from the outside.
how do i rectify this fault ?
failing that...
which fuse do i pull out to conserve my battery power ?
grateful for any assistance regarding the above.

 

[wireman]

The lamps are connected to the multifunction relay which is in charge of all the curcuits which are time controlled, it is at the very back of the fuse box, the wide black unit just about big enough to hide a fag packet, off the top of my head I can't tell you which fuse supplies the circuit but you should be able to find out by examining the fuse box lid.

One of the following circuits fuse may be the one to pull for a temporary fix.
The hazard flashers, turn indicators, delay wipers, screen wash and heated rear glass are they all behaving normaly? these are all controlled by the one relay unit which having sensitive electronic control inputs can be triggred by moisture in the fuse box.

My 190 had random faults on all the above, signal a turn and the windscreen got washed, turn on the heated glass and the seat belt lamp lit etc.
The fault on mine was caused by water entering the fuse box through a cracked lid hinge, it was cured finaly by replacing the entire fuse box @£10 from a scrapper.

It was not the only 190 I've seen with the fuse box lid left un sealed but was the worst for electrical sillyness untill the fuse box unt was changed.

 

[longlostpoet]

thanks Wireman,
have located "No 13" as the faulty fuse !
but....
as you say, other function affected by this removal of fuse.
in this instance, the hazard flashers cease to work also.
will check condition of relay & fuse box when weather improves...
fingers not working properly in these artic conditions....

 

[wireman]

Correction

My apologies the information I gave you before is not quite right,
I've had a look at my bits of wiring drawings.
The timer for the interior lamp is inside the lamp assembly. It gets its feed from the fuse box directly but also takes a feed from the ignition circuit and its is unlikely (but not impossible) that the fat relay is innocent.

The electronics in the lamp housing (its firmly clipped into the roof lining) has wires for power, ground, switch contact, ignition, interior bulb and seat belt bulbs.
The electronic module:-
senses the door opening and switches on the belt light for a fixed time,
senses the door closure and delays the lamp switch off,
senses ignition on and immediately turns the interior lamp off .

If you can survive without those bells and whistles it is possible to remove the wires and get rid of the module.

There is a plug connector onto the lamp assembly if you remove the lamp it can be disconnected and your fuse replaced.

 

[longlostpoet]

are the seat belt bulbs removable ?
they must be replaceable but what i mean is...
if the seat belt bulbs are removed completely, does it do any harm ?
if not this would solve the problem whilst leaving all other facilities working OK.
what are your thoughts on this idea ?
*
i am most grateful for your helpful posts. thank you !

 

[longlostpoet]

well,
taken bulbs out of "seat belt warning" set up.
everything else works OK.
*
so far...........
any pitfalls that i should be aware of ?

 

[wireman]

The interior lamp unit may still be drawing some current, it should only be small and of course without the lamps it will be much smaller, but without measuring and ensuring its very low, there could still be a possibility of the battery getting discharged whilst the car is parked, a fully charged battery contains about one kWh (just one unit) of usable energy and that does not go far when abnormal/unwanted loads are left connected.

 

[longlostpoet]

thanks, will get it checked !