Volvo Coolant Level Sensor: 3547710

93Regina · Post by **93Regina** » 29 Feb 2016, 12:00

Anyone know how this works electrically?

93Regina · Post by **93Regina** » 29 Feb 2016, 20:52

Apparently, a magnetic float is contained inside tank, and a continuity signal (ground pass thru) is provided when magnetic float drops down. A low current bulb would be used within instrument panel.

Here are several means to setup one: Coolant Sensor for Volvo 740/940 Cars

For 940s, I'm not sure if the info is correct in regards to "b) Volvo 940 with Rectangular Tank P/N 9142001/2." Maybe Volvo updated numbers, but current numbers I see for this tank is 9122997, along with required sensor, 3547710. Some $80.00 in OEM parts.

Here is a DIY tank using a different type of magnetic sensor, but it operates the same way electrically. One side of tank-sensor wire is grounded, and other wire goes to instrument panel, where one side of light bulb has 12 volts.

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93Regina · Post by **93Regina** » 29 Feb 2016, 20:55

Footnote - With time, the magnetic breaks apart, and then it doesn't work.

Post by **MadeInJapan** » 13 Aug 2016, 23:52

I know this thread is for older Volvo's but I'm looking to install a float sensor in my S40 reservoir tank (2007 model) which to my amazement, doesn't have such a sensor as an early warning. I have chosen the buy a vertical sensor and not a horizontal one like the diagram above due to the limited space inside the reservoir that comes with my car. If things are successful, I'll post back here and possibly, I should port this over the the appropriate section of this forum. I suppose one reason I'm writing here is because the original post was very helpful for me in making my decision regarding what parts to buy for now.