abs gone nuts???

had the abs light on since i got car (its 300tdi auto on an m reg) with mot time looming i thought i'd better take a look read fault code using self diagnose function which came back as NO SOLENOID VALVE SUPPLY-SYSTEM RELAY. So i checked relay to find it had a dodgy connection, fixed that, cleared fault code then went for a drive. but the light was still on so read ecu again to get response that FRONT LEFT WHEEL SENSOR-AIR GAP. So i gave sensor a tap and again went up road but the light stayed on. so read ecu again but no code stored. the abs is functioning as it should but light won't go out, it also doesn't do its check function when turning on ignition (ie comes on the goes out briefly then back on till vehicle moves) instead it just stays on. so under the assumption that the abs is fine i decided to check connections to the warning lamp relay. now this is where it gets tricky if i'm reading my wiring diagram properly there should only be one live which should be relay terminal 85 and with relay removed bridging terminals 30 and 87a on the plug should extinguish tha warning lamp the problem i'm having is that i can't find any reference to the voltage i should have at terminal 30? terminal 30 is showing only 2 volts and if bridged to terminal 87a the warning lamp merely dims slightly. the relay is fine as we've bench tested it. so if anyone could enlighten me as to the voltages on this relay connection and any fluctuations during ignition switch on (when abs lamp should flash i would expect the power to the relay to alter briefly ) i would be greatly appreciative.

hi all, accidently sorted abs problem today it turned out to be the warning light relay as i suspected. i was checking the power supply on the relay connector when one of the lads at work asked what i was doing so whilst explaining i turned the ignition on as i was running through what i'd done already. to my surprise the abs light behaved as it should actually extinguishing then coming on again' i still had the test lamp connected to the live on the relay plug, so i drove the car out of the garage and the light extinguished. so i bought a new relay and everything is now sorted. strangely though the old relay works fine as i'd checked yesterday. but system only works with new relay. so i can now get the mot sorted without anything major to worry about.

bedtime stories are allways better when they have a happy ending

i'm really pleased i got it sorted today i can actually sleep tonight rather than spend it trawling web for answers to a problem i didn't completely understand.