Hi, I took the battery out of the car over this last snowy period (on the advice of my father in law) as I would not be using it. I tried starting it the other day & it wouldn't turn over. the lights are bright so battery fine i think. Would disconnecting the battery mess up the NATS/Immobiliser? The key is not a remote locking type but has a little blue bit on its side, probably for the battery? Any help much appreciated.
The immobiliser would not be affected by the battery removal.
Check the battery connections are not corroded and tight.
The lights could work with a bad connection, but the extra current drain of the starter motor will show up any connection problems.