I refer to the letter from DH, Bridgend regarding a 2005 VW Golf with "an array of warning lights that have been coming on together, intermittently". The discussion was around possible faulty sensors or the ABS unit. We too have had this sort of problem. My wife's car is a 2002 Golf Mk IV 1.6 petrol with less than 60,000 miles.

The car would exhibit a sudden loss of dashboard illumination and various warning lamps came on such as ESP, ABS and the exhaust emissions lamp. Whilst it appeared to be random, it was usually in cold and wet conditions. I first disconnected every connector in the engine bay and sprayed with contact cleaner. Then I remembered that years ago problems were usually fixed by finding a bad earth connection somewhere.

So I went looking for the earth points in the Golf - and found three under or close to the battery. It was quite an easy job to remove the battery and the plastic case around it. When I finally accessed the earth points, which are studs, each with at least one wire crimped with a ring connector, I discovered that one of them was especially corroded.

Using emery cloth I restored the studs and the rings to shiny condition and reconnected.