Hi All I have had the opportunity to study the fan fail module as I had one in my car when I bought it. The interesting things about it are as follows: Although the fans are wired up seperately to the socket, they are connected together inside the module. The primary reason for the fan fail module going wrong is the pathetically small solder joints where the pins for each fan are connected to the board. Combinations of flexing when plugging them in, and the heat generated by the small connection results in these solder joints going "dry" - ie not proper electrical connections, merely touching contacts. I was however heartened to see that the original module did employ proper hall-effect current sensing to light the fan fail light. It does not light the fan fail light if something goes wrong with the main power relay supplying the fans. As I mentioned a week or so ago, I have designed and am in the process of constructing a DIY fan module for sequential fan engagement, and an additional system for detecting a failure in the fans. The circuit is so elegangtly simple that anyone who knows how to use a soldering iron should be able to build one. 75% of the problem with projects like this is sourcing appropriate components! I have also incorporated "options" into the design after some comments I received. Watch this space. In other news, I have also designed a replacement for the lock module - again something anyone with soldering experience should be able to construct. I will be testing all my designs and instructions on a friend who knows how to solder, but not electronics as such. All the best Martin #1458