I wanted to create this post, because it shows how my car was readied for its IVA. If you have problems like this during your build and are sending your car to PBC, you could leave them to Caterham (or their agent) to sort out. However, if the problem is found to be because of your build, then you will be picking up the bill.

I have been fortunate enough to see a copy of the Caterham PBC check list, so I decided a good way to prepare for the IVA was to work my way through that list.

First item on the list: “Check the handbrake warning light is working and adjusted correctly”. A simple check, and to my surprise I was off to a poor start, when the handbrake warning light failed to illuminate regardless of the handbrake position.

Obviously, my initial thoughts turned to my own work and I questioned myself whether I connected the warning light switch correctly. Thankfully, I have taken hundreds of photos for this blog, so I only needed to look back on them to find the proof thatI had connected correctly.

After the problems with my oil pressure gauge, Caterham had kindly provided me with some of the up to date wiring diagrams. They did not give me the full picture, but fortunately allowed me to piece together what was going on.

The handbrake warning light doubles up as the low brake fluid warning light, so testing the wire that illuminates it is simple. The light should illuminate when the black and white wire is earthed, either by the handbrake switch or the low brake fluid switch. My multi meter proved the handbrake switch and wiring was working correctly, all be it with a little adjustment needed to get it working before first click.

Therefore the question was whether the tachometer was connected to the black and white wire.

Finding the black and white wire where it’s connected to the chassis loom into the gauge loom was not easy. I took random photos under the dashboard until I finally found what I was looking for. Disconnecting the connector and testing it with a multimeter proved a good connection.

Testing the connection at the back of the tachometer

Therefore, the final test was with the connector at the back of tachometer. I removed it from the tachometer and once again I had a good connection, so I knew that the problem was with the tachometer.

Caterham kindly sent me a replacement tachometer (although they were skeptical about my diagnostic abilities), and once replaced, my handbrake warning light was working as desired. Interestingly I also saw the ignition warning light working for the first time, something that was obviously always a problem, but I just hadn’t noticed it before.