Hi, 08 1.8 zetec, interior light comes on when switched to on, but when in central position (courtesy) the light will not go off.Anyone any ideas what could cause this?

a faulty switch on a door. do you get any warnings on the dash saying a door is opened?

i cant see the light itself being faulty as there is only one live feed and 2 negatives. (tested with a multimeter on mine). the switch itself just moves a connector to each neg or none to stay off.

so a faulty switch on a door would be where i start looking.

a faulty switch on a door. do you get any warnings on the dash saying a door is opened?

i cant see the light itself being faulty as there is only one live feed and 2 negatives. (tested with a multimeter on mine). the switch itself just moves a connector to each neg or none to stay off.

so a faulty switch on a door would be where i start looking.

thanks johnH. I do not get any warnings on the dash, unless i open a door. was beginning to think it was the light unit itself.

So if you set it to permenant on - it stays on - permenant off - it stays off - but "door" mode - it constantly sits on? sit in your car close the door, and deadlock the doors, your indicators will blink twice - does the light go off then?

So if you set it to permenant on - it stays on - permenant off - it stays off - but "door" mode - it constantly sits on? sit in your car close the door, and deadlock the doors, your indicators will blink twice - does the light go off then?

thanks. tried this but the light stays on.

Sounds like a wiring issue, maybe the switches on the doors are being pressed in, but the signal isnt getting to the ECU / Relays. as silly as it sounds, give the door catches and everything a quick once over with WD40, if you lubricate the sensor and if its partially stuck / not registering fully when pressed in, you might loosen it off enough to start working again.

Other than that, you would have to trace the wires all the way, to find the offending door, and then trace to find where the wire is brokrn...

jee's on the mark...once again

i would personally (if viable), get a multimeter and check each door sensor to make sure the switch is acting as it should. that will then point to you the culprit.

EDIT: on speaking to my dad, he says he always gets this on the buses when a wire on a door switch has come off. he said basically take door switch out and check and reconnect.

Most likely cause is the GEM if the 'door open' warning is not displayed on the dash.

GEM uses open collector (Transistor) output to control the lamp and I guess its blown, have you installed additional interior lamps, excessive loading is just about the only thing that would cause it to blow.

Unfortunately the GEM controls other stuff too so its not a cheap thing to replace.... This is when you wish Ford still used individual pretty coloured relays scattered around the car.