Hi m8, the below is from a post i did a while ago. It describes
how to "wire" the gauge, then all you need to do is "plumb" it into your DV vac hose.
Please Note: the information below is for the Autogauge "gradational" series, 7 colour change). They can be purchased from most Halfords stores, for approximately £20-£25. The gauges come with the necessary parts to fit them and make them work (i.e. t-piece and piping for boost guage, and temp. sender for oil temp).
http://www.halfords.com/webapp/wcs/...rentcategoryrn_70561_crumb__topcategory_70561
As for the wiring...see pics below-
The gauge has the wires below:
Black - earth
Purple - turns on illumination for the needle
Orange - turns on illumination for the dial numbers
Yellow - memory wire to remember what colour you chose
(note: the dial numbers will only illuminate if both the orange and yellow wires are connected...orange alone will not do anything).
So as per the pics below-
Yellow wire to red permanent feed in pic below
Black wire to brown earth wire
Purple and orange to blue/grey from dimmer plug (this allows the dials to dim along with the standard dash lights).