warning lite in the dash...wont go out..but my lite bulbs are ok..parking turn, hi/lo, rev, brake

1987 765ti



so this little thing wont go out........


the warning bulb that says you have a lite out.....I don't....but the
bulb will not turn off....wanring bulb that is...

now, the lite bulb comes on when I turn on the parking lites...and it
stays on....


what could be wrong?

take out all bulbs, and dielectric grease all contacts?
fix rear licencs plate lites?
drop back 10 yards and punt?
the console, ashtray front and back, and the glove box don't work...but
I don't think it would be that....


any one else have this problem?

any ideas?

thanks

 

A very common problem. Any imbalance within a pair of bulbs (front pair or
back pair) will cause the light to come on. You can determine whether it is
the front or back bulbs doing this by removing either the parking light
bulbs *or* the tail light bulbs and see if the symptom goes away. If it goes
away, replace both of those bulbs with a brand new pair. If not, leave those
out and remove the other pair. Now if the symptom goes away try putting the
first pair back in. If all is okay with the first pair back in, replace the
second pair with a brand new pair. If the symptom never goes away or if it
returns when you put the first pair back in, remove the "bulb out" detector
and resolder the connections inside or replace it with one from a wrecking
yard.

If the problem is isolated to the parking lights or the tail lights and
replacement doesn't help, carefully work over the contacts and grounds for
those bulbs.

Mike

 

roger that!

I am gonna check this out,,,,,,hop eit works.....


thanks!


al

 

Alternate solution is the lazy one: don't worry about it but do a
regular walkaround and check the lights.

The perfect time to do this is when you do your regular weekly checks
on fluid levels and tire pressures.

Oops! Let me guess. You don't have that regular weekly habit -- don't
worry, most drivers don't but should. Me too! I'll admit that ($-<....

 

Still difficult to check the brake lights, unless you have something
shiny behind you.

 

Brake lights work with the engine off so you can test them in the garage
with the door down.

 

Just back up to a large plate glass window at night, most any store
will do, and hit the brakes. The key is to do this in the dark!

 

Check the fuses! Same thing happened to me in my 1990 240, and all the
lights were fine, but 2 fuses were blown. Didn't figure it out for 2
months (I hardly drive), took 3 seconds to fix!

loren

 

I've had so many "lite-out alerts" over the years that I carry a wooden
stick that I can wedge between the front edge of the driver seat and the
brake pedal, to hold it down. Then I walk back and see which brake light is
out. Unfortunately, I recently noticed that when I lift the tailgate ('89
240 wagon), the center brake light flickers or goes out, so I'm guessing
I'll have to replace the flexible cables into the tailgate sometime soon...
any suggestions?

 

I recently replaced a headlight on my '83 245 with one I had kicking
around the garage.
The lamps in it are generic sealed beam (sealed... lol, I had to replace
the one that was ¼ full of water.) The one I put in was one of those
expensive "quartz" lamps.
The warning light still comes on when I turn on the headlights. Both
lamps work.
S'pose having a quartz one on one side and a clunky old sealed beam on
the other can cause this too?

 

That would do it because the light out unit works on detecting the current on
the left and right sides are equal. If they are unequal it will trip the
alarm. Different bulbs can draw different currents. If you have a nervous
light out unit that seems to have a mind of its own it would be prudent to
remove the bulbs and bulb holders and clean the contacts. Sometimes it the
bad contact that causes a current imbalance.

The rear tail light assembly is quite a horrid design. For each bulb there
is a set of contacts between the holder and the flexible PC board and between
the bulb and the holder. Than there is the main connector for the harness on
the flexible PC board. Lot of potential for things to go wrong and they do.


Regards,

Boris Mohar

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

void _-void-_ in the obvious place

 

Don't I know it... My right rear brake light refuses to work. I've
replaced the bulbs, fiddled with the connections, etc... as much as one
can do squeezing into the little access space.
Going to have to pull it out and work it over proper.

 

If you're lucky enough to have a garage, and it isn't full of other crap.

I did say something shiny behind you helps, I suppose in the dark any
sort of wall is shiny enough.

 

Yeah, replace the harnesses in both hinges, you pretty well nailed it
down. It isn't particularly difficult or expensive.

 

Yep, even different brands of otherwise identical bulbs can do it, the
sensor is very sensitive, too much so.

 

Check the connector that plugs into the light assembly. Sometimes the one or
more of the contacts will wear right through the printed circuit board pads
that make the contact with the connector pins. I repaired few with adhesive
backed copper tape from stained glass supplier and some careful soldering.



Regards,

Boris Mohar

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

void _-void-_ in the obvious place

 

Not really -- the old deadman-switch over-ride (toolbox on brake
pedal.) All you need is enough pressure to drop the pedal far enough.
Of course, it does take bit of time (five-ten minutes) to check
everything but not hard.

Backing into the garage and tapping the brakes (especially with a
convex traffic mirror positioned properly) but I don't have a garage....