Today i installed a head unit into my vl and as a result the tail lights and the dash lights dont work now any advice will be appreciated.

Check wiring on head unit? Did you use existing power from old (original) head unit or run new lines?

used the original loom from the factory tape deck

Pull it out and go over it. You have done something you shouldn't have.

went over the wiring today and found if i unplug the head unit its fine no blown fuses but then i plugged the head unit back up and as soon as i hit ACC the fuse went as a result my dash lights, parkers, tail lights go out. anyone shed light on this problem?

Wiring between head unit and fuse is shorting, or your head unit is fried. Obviously if there's no current flowing through the harness (ie, head unit not connected) the fuse wont blow.

i dont know man in not real gifted in the elictrial department do you think it could be the head unit it self because i got it from my mate its not new but it was working when it was takin out of his car or you reckon its wired up wrong?

It's pretty hard to tell over the internet, if you're not confident with it, get a mate to help you, or you might have to take it to an auto sparky

my brother who is a mechanic reckons its the head unit is wrecked but i think it has just been wired up wrong i was just wondering if anyone had ever had the same problem or a solution to save me some time and money

today i went to go for a drive jumped into the pos checked to see if the tail lights etc worked and i left them on they were fine seeing as the head unit was disconnected the went to start it and everything just went dead nothing works wont even start .....

Figured out the problem faulty earth... the old earth worked and was a solid connection non the less decided to run a new earth and problem solved everything worked fine now waiting on my brother to solder it all up and job done.