Upgrading headunit

[JB G60]

Hi,
Have two 88' 8avlavers and a new enough blaupunkt head unit. both the valvers have power going to the headunit (as i got a spark when I hit the + and - together) but the radio just wont turn on in either of them if it was just one car it wasnt working in I could figure it out but the fact that neither of them work is just very strange .
any help would be great

[rowlers]

shorting the 2 wires together has prob blew the fuse feeding the live!

check fuses and use a multimeter to determine you're live and grounds.

[JB G60]

I only did that to make sure there was power. i replaced the fuse straight away.

[rubjonny]

you probably need an ignition live feed to make the units power on, which is missing on a MK2.  Easiest place to get one is by splicing into the black/red wire on the blower motor switch
If its an early MK2 with the hazard switch on the dash, round the back of the fusebox you'll find several unused spade terminals, one side live, the other ign live. See here, G = ignition live, P = Live (terminal 30):
http://www.bentleypublishers.com/tech/vw/bentley.vw.fuse.panel.rear.1984-1993.htm

If its a late MK2 with the hazard switch on the steering column, there is a 'key in ignition' feed on the ignition switch which is not wired in, if you cut the plug off another car in the scrappy you can splice the required wire in 

Edit: Oops, wrong wire  :embarassed: