Low windshield washer fluid light.

1989 260E.
The ''low windshield washer fluid'' light is always ON when I put only the parking lights on.
Goes off when headlights are ON. Fluid is full, sensor is new.
I think my car is starting to show some signs of old age?
Any idea???
jackD

[xp190]

I would check the wireing, I had a similar problem with my windshield washer pump, would only work when the lights were on, turned out it was a rusted ground. Fixed it up, pump works as new. The ground was very cleverly hidden under the headlight.

xp

[scanny]

Check to see if one of your parking light bulbs is burned out. The windshield-washer-low light is reversed with the bulb-burned-out light on some models, including my own.

The problem is solve. Cause: bad contact of the sending unit.
jackD

[CSchmidt]

Jackd,

On my '87, it came with "clear" washer fluid. I replaced it with standard "blue" washer fluid. The low fluid light comes on. After some testing, I found out Mercedes sells concentrated washer solution you mix yourself (yup the "clear" fluid). My guess is the alcohol content in the blue fluid is less dense, so the level sensor in my car sinks, light goes on. Put the MB water based solution back in and light goes out. May be an old sensor, but I am living with the clear solution at least until winter sets in. Let us know what you find out.

Chuck

I can't see why the color of the fluid whould have any effect.
The blue color is only a dye.
Both fluids (mercedes and others) are water and alcool only.jackD

[CSchmidt]

jackd,

The Mercedes fluid was a concentrated soap, maybe 4 oz to be disolved in a gallon of (my) water at home in my container. The stuff you buy (typically blue) does have a high alcohol content to prevent freezing. With the water based solution my washer fluid sensor floats, so no warning light. With the blue, less dense alcohol based fluid it sinks and the light comes on. I took the sensor out and tested it with an ohm-meter in each fluid.

OK, now for the next obvious question,... does a new sensor change this condition (work with the alcohol solution). Anyone tried a new sensor?

(BTW- this is on an 87-300sdl)

Chuck