the abs light is on on my 3 door sierra all the time, how do you test the sensors to see if they are working, i can not take the car for a run as its got no mot its got new pads all round new calipers the brakes work, or can i disconnect the warning lights ?

 

if you want light off unplug from centre of binnicle/clocks -clocks have to be out for this
you can do a continuity/break out box test on sensors-but if it comes on at a standstill its more likely ecu,pump/sensor related-does pump power up[you will here it] as you need that

 

yea the pump powers up you can hear it,

 

as long as pump works-its the plug directly in centre for bulb

 

The sensors should have at least 1K Ω. You can check this at the ECU, if you lookup the pinout.

No, the light needs to be working to pass an MOT.

Martin

 

If you have wiring diagram it's not too bad to test, start by unplugging sensors and check resistance, open circuit will be no good, then check for same at ecu plug to confirm wiring ok, if pump runs and cuts out when up to pressure then that should be ok, another common problem is the level sensor on the cap or wiring to it. The system itself is pretty simple and not hard to troubleshoot. An open circuit sensor is usually the culprit, front plugs are under wings and rear are under back seat.