Hi i was driving the other day and the rev counter and speedo  stopped working and all the warning lights came on for a couple of mins then the speedo and revcounter started working again all the warning lights went off except the air bag warning light stayed on.

Has anyone any ideas on what the problem is 

Here is one suggestion that is likely but there are others too such as a poor solder joint in the dash panel.

 

Take a look at the large fuses near the battery and the large cable that comes from the alternator to one of the fuses.

 

Corrosion at the cable end will cause it to overheat and this usually shows as melted plastic in the fuse carrier. The high resistance in the alternator cable will limit the max charge current into the battery. If you have a large discharge current (lights plus heated screen for example) the battery will slowly discharge to a voltage where many electrical components (such as the dash display) will not function correctly. Common problem on VAG cars and a search on here will provide more information. You MUST replace the cable for a long term fix although if the cable is long enough you could cut back to clean conductor (not black) and re-crimp. Replace the fuse carrier too.

I would be tempted to suggest battery/alternator issues (and maybe charge cable/fuses on the battery, as mentioned above)

Thanks for the info i m going through it today