I am also having a similar issue. there are no lights at all on my dash when my engine is running, but when i turn my keys off and even remove them the ABS light is on faintly. my ignition barrel feels a bit sticky too. it is a 2001 ford transit minibus 2.4tddi with 474000 miles on the clock.
i had a few issues with it. back in october it failed to start, it would crank but did not start. luckily i had another transit van. i use the van to tow the bus and it started in second gear by releasing the clutch at around 10 mph. drove it back home fine. got home. turned it off and tried starting it again. just cranking. it was late so i gone to bed.
next day, i removed the good battery from the van and fitted it in the bus. go to start it. nothing at all. no dash lights or anything. on the 2001 transit in the UK the battery is under the drivers seat and the jump points are under the bonnet (hood) we tried frantically to get them back on again which we did briefly and managed to bump start it. but then filled the tank to the brim and then not starting and no dash lights again.
a back street mechanic tried joining up 2 jump cables together to connect to the live on the battery to the live jump point under the hood. it given the dash lights again but will only start on a bump start. turned out to be a break in the live feed for the problem with no ignition lights.
however, we changed the starter motor and removed the jump cables and the dash lights were fine and started off the key as normal.
then 6/7 weeks later i been out working in the bus all day. i park up and turned the engine off and all the dash lights were on bright and a continuous beep which would disappear when i turn on the ignition with my keys. it still started. so i decided to disconnect the battery while i was parked up for couple hours. came back to go home. connected the battery up. lights were back on with the keys in. wouldnt start not even a crank. rang for help. it got late and got a lift home with the plan that i would use my other transit to drive back down with a friend and tow the bus back home. but must have been a bad day as the van wouldnt start neither. ended up using public buses to go and try my bus again. dash lights were still on but the bus unlocked. luckily i had a solar panel and connected that up to the battery the night before. tried starting. no luck, so we decided to push it as far as we can up the slope in the car park where it was and try a bump start. didnt get enough speed so didnt start. decided to give up, tried with the key one more and it had started up with the key. needless to say i drove home as quick as i could.
got home that night. the dash lights were still on but faint. i pressed the foot brake gently and the ignition lights gone out when no keys in. released the brake. turned the key and it started up still. i repeated this 3/4 times and it was fine and the ignition lights have gone out as normal when i turned off the ignition. next day it was fine until i had tried jump starting my other transit. the other transit failed to start and made a clicking sound. i turned off the engine while the cables were still connected. gone to start the bus again after giving up on the van. it struggled to start after i removed the cables but still started. gone to go out in it again later and then no crank at all and the ignition lights came on and off as they should.
few days later i got an auto electrician out. he diagnosed the starter motor was bad again as not spinning. he fitted a second hand on and it worked fine but, last night after i been working all day. i got home turned off the engine and noticed the ABS light was on faintly. if i press the brake it goes out and comes back and flicker slightly when brake peddle is released. if i turn the ignition in certain position to turn it off, the lights goes out. i also noticed too that sometimes after i removed the keys and the ABS light is on faint, the engine temperature gauge goes up to normal temperature but goes down when brake is pressed.
i been out today and tried the bus. the light was still on, still doing the same and it still started. i also still have my solar panel connected to my battery. a bit of luck i wouldnt be left stranded with 14 passengers miles from home until i can get it sorted.