I am hoping someone might be able to shed some light on a switch that is attached to the brake master cylinder of my 97 850. This is my 3rd 850 and the previous two (83 and 84) both had pedal position sensors attached to the booster but did not have this switch on the MC. This car does not appear to have a pedal position sensor.

In looking at parts for an S70 I see a reference to a Brake Pressure Switch (part number 9173210). This looks very much like the switch I refer to. If I do have a brake pressure switch on my car what is its purpose and if it has failed could it be the cause of my ABS light coming on intermittently

I realise there are a myriad of possible causes for an ABS light but I'm trying to eliminate the least expensive first.

Any advice would be gratefully received

Tony

No, the failure of the brake pressure switch will turn on the brake failure light in the instrument panel.
Get you codes read at any autoparts store and try to clear them. It is just possible that your ABS module is going away.
http://home.earthlink.net/~vicrocha/
--
My name is Klaus and I am a Volvoholic.

If something is causing your ABS light to come on, there should be a code in the OBD system. Have the codes read somewhere, and see what it says.

not a myriad of causes -bad solder inside the abs unit.
it should have been a recall
--
'97 855na, Mobil 1, K&N, various IPD's and eBay's