Moving right along, it is now time to install the Engine/Transmission control computer and it’s wiring harness. No major issues here other than the size of the wiring harness where it makes it way through the firewall, the size and position of the HAVC unit and all of it’s hoses and wiring are all quickly taking up all of the space behind the dashboard on the passenger side.
Computer and Wiring Harness Install
On the plus side, the harness that was supplied by Hotwire.com is very well made, has all of the right connectors and all of the wires are cut to the proper length. The owner of the company had asked me when I bought the harness where I wanted to install the computer, either in the passenger side kick panel or under the rear seat. I opted for the kick panel and Tony Squire provided just the right amount of wiring to properly install the computer in the kick panel – not too long nor not too short.
Once the wiring harness was in place, I needed to locate a good area to mount all of the relays that the computer needs and also the ones for the HVAC unit as well. The logical place for the relays was on the inside of the firewall mounted near the top. I was concerned about punching a bunch of holes in my nice clean firewall to handle the mounting screws. So, I fabricated a hat section out of sheet metal and welded 10-24 nuts on the back side to accept the mounting screws. I used panel adheasive to attach the hat section to the inside of the firewall leaving the engine side clean and smooth. Once I had installed the HVAC unit I noticed that it shrouded the relay connectors and most of the relays, so the next time I had the HVAC unit out, I repositioned the relays with the sockets pointing up, which also gave me a bit more slack in the harness in this area.
Mounting the Relays on the Firewall
With her new brain installed, my old 1956 Dodge Sierra station wagon is now a more like a 2005 Dodge Magnum, so what was an old mid 20th Century family hauler is now an up to date 21st Century long haul 4 passenger cruiser.