Windscreen Washer Level Sensor

Chris139 · Oct 7th, 2003, 22:04

How does the Level Sensor in the Washer Bottle actually work ? I thought it would be a float-type system but it isn't. A blue wire and a black wire are joined inside the bottle by a moulded piece of plastic about 2 inches long. How can this detect the level of screenwash ?

Cheers,

Chris
1998 V70 2.5 20v auto

sholtby · Oct 8th, 2003, 07:26

A small current flows between the 2 wires when there is coolant between them. This keeps the warning light off.

Simon

Chris139 · Oct 8th, 2003, 13:13

The bulb is OK on the dashboard as it tests itself when the ignition is turned. At the sensor's connection there is indeed a small voltage when the engine's running (2V). However, when the sensor's disconnected (and therefore there is no current flowing between the two wires) the light still doesn't illuminate.

So, I'm getting 2 volts at the connector and when the sensor is unplugged I'd have thought the connector was an 'open' circuit and would've triggered the light.

sholtby · Oct 8th, 2003, 22:03

I'd have thought disconnecting the sensor would have brought the light on also.
Sorry,I was relying on experience with previous cars they have always had either float sensors or measure the resistance between 2 probes.

Oct 7th, 2003, 22:04	#1
Chris139 Member Last Online: Feb 18th, 2010 15:52 Join Date: Dec 2002 Location: Stroud	Windscreen Washer Level Sensor How does the Level Sensor in the Washer Bottle actually work ? I thought it would be a float-type system but it isn't. A blue wire and a black wire are joined inside the bottle by a moulded piece of plastic about 2 inches long. How can this detect the level of screenwash ? Cheers, Chris 1998 V70 2.5 20v auto __________________ Current:- 2004 S60 D5 S (163bhp) Geartronic 1994 855 2.0 20v GLT (140bhp) auto Previous:- 2000 S80 2.4 (170bhp) auto 1998 V70 2.5 (170bhp) auto

Oct 8th, 2003, 07:26	#2
sholtby Premier Member Last Online: May 26th, 2010 20:17 Join Date: Dec 2002 Location: north east	RE: Windscreen Washer Level Sensor A small current flows between the 2 wires when there is coolant between them. This keeps the warning light off. Simon

Oct 8th, 2003, 13:13	#3
Chris139 Member Last Online: Feb 18th, 2010 15:52 Join Date: Dec 2002 Location: Stroud	RE: Windscreen Washer Level Sensor The bulb is OK on the dashboard as it tests itself when the ignition is turned. At the sensor's connection there is indeed a small voltage when the engine's running (2V). However, when the sensor's disconnected (and therefore there is no current flowing between the two wires) the light still doesn't illuminate. So, I'm getting 2 volts at the connector and when the sensor is unplugged I'd have thought the connector was an 'open' circuit and would've triggered the light. __________________ Current:- 2004 S60 D5 S (163bhp) Geartronic 1994 855 2.0 20v GLT (140bhp) auto Previous:- 2000 S80 2.4 (170bhp) auto 1998 V70 2.5 (170bhp) auto

Oct 8th, 2003, 22:03	#4
sholtby Premier Member Last Online: May 26th, 2010 20:17 Join Date: Dec 2002 Location: north east	RE: Windscreen Washer Level Sensor I'd have thought disconnecting the sensor would have brought the light on also. Sorry,I was relying on experience with previous cars they have always had either float sensors or measure the resistance between 2 probes.

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