hmm, thats a bummer cos although Ive been trying to keep a rough log of the mileage, after my bump last month the insurance company isnt too happy with the odometer not working. - Ive got an agreed mileage policy & while they have accepted the dash has a fault at present, they are expecting me to fix it ASAP. Looks like Ill have to give up on this DIY idea & pay someone to repair it or buy a 2nd hans / new dash!
phoned a guy in glasgow ages ago that does mileage correction but he said he cant guarantee he can fix it but he would have to unsolder something & it will be £150.
I agree it does sound more like an instrument cluster fault. What kind of car have you got? Early Audi TT 8N were notorious for this. Have you tried all the usual obvious stuff like running a fault code scan on the instrument cluster to see what is returned then clearing them, or pulling fuses/disconnecting the battery for a time to see if that clears it?
TTQS