Solid State Relay Board Options

[Steve_R]

Well, it’s been about a year since I finished my 914 restoration, you can read all about it

HERE.

Everything works perfect except for the electrical problems I’ve been having with the relay board. I spent lots of hours trouble shooting electrical issues with the fuel pump. It turs out that my relay board had some bad connections for the fuel pump relay. After searching this site I discovered that the relay board is truly the weakest link in the 914. I tried to remove the epoxy bedding underneath the board and resolder the connections. This worked for a while but the fuel pump would sometimes stop and kill the engine. I finally figured out that the contacts for the fuel pump relay to the board were causing the problem. This seems like a never ending problem. I could buy another 40 year old used board and have the same problems.
So, to make a long story short, I decided to design a new relay board from scratch. I replaced the original electromechanical relays with industrial solid state relays. They have the same connection labels as the stock relays: 85 & 86 for the coil and 30 & 87 for the switch. The relays are available at most electrical parts dealers like Mouser or Digi-Key if one ever needs to be replace. They also use a lot less power than the original 914 relays. Also, since they are solid state and don’t have any moving parts they will last a lot longer and are more reliable. I also replaced the old ceramic fuse with a modern ATC style fuse and added an LED that illuminates when the fuel pump has power. This is great for trouble shooting fuel pump issues. It comes on for a few seconds after the key is turned on and stays on when the engine is running. Also, I removed the connections and plug for the rear window defroster. I used wires soldered to the connectors eliminating all of the riveted connections. All connections are soldered. To make the board I CNC machined the board out of high density polyethylene plastic.
I built a few extra boards to offset some of the development costs. They are quite labor extensive to build so I don’t plan to mass produce them. PM me if you want one. I would like to get $500.00 each. That includes the board with the solid stare relays. It does not include the voltage regulator. I used a solid state one from Pelican Parts. Both the stock and solid state voltage regulators will work.

[N_Jay]

If I can get the pins for the body and engine connectors, I might try just building one by hand out of plexiglass sheet.