My work van developed an electrical fault a couple of weeks ago, basically a whole host of warning lights came up on the dashboard including ABS & traction control, and the cigarette light and speedo stopped working. As it's less than 2 years old I took it back to Vauxhall as it's still under warranty. After they'd had it for a couple of days they said they had found the fault and a replacement part was order and would be fitted tomorrow. After chasing for nearly a week they told me it was a major electrical fault and they would have to get a specialist to come and look at it. I asked if i could have my van back so i could get someone else to take a look at it, and also explained it was my main source of income and i needed it back urgently, but i was told it was in the workshop in bits and even if they put it back together i still couldn't drive it with the electrical faults. Then after nearly 2 weeks without a van, they told me it was caused by water getting into a cracked back light and it was not covered by the warranty and i'd have to pay the £485 repair bill? I quizzed them as i couldn't see how water getting into a light could cause so many electrical faults and why it took them 2 weeks to diagnose? After several hours backwards and forwards on the phone they agreed to knock £15 off, so the repair would only cost me £470 !! Unfortunately i'm self employed and my van is my source of income, being without it has cost me several £1,000's in lost income and i couldn't be with it any longer so i agreed to pay. When i arrived to collect it the cracked back light was still not repaired. When i asked why they hadn't replaced it, if it had caused all the problems they told me it was not the back light but it was because i'd knocked the interior light in the back of the van and caused a short curcuit? So now i'm £470 worse off I've lost 2 weeks income and I've still got a cracked back light.

What i can't work out is how a fault with a light has effected so many different systems including the brakes, surely any system associated with safety like ABS and traction control should be on a separate circuit and protected by a separate fuse? Also how did it take them nearly 2 weeks to diagnose the problem? I'm convinced something doesn't add up, i think there might me an underling fault and they have blamed the back light and interior light to make it out to be my fault so i would have to pay for the repair, but how can i prove it?