Have someone with sandcar experience look at it before buying it. If you don't know what your looking at it is hard to tell the difference between a good deal on a good car or a worn out car with problems. Even old guys will lie to your face. Do they have receipts for maintenance and or parts...
You have to have certain voltages on the two ‘control’ wires. Some of the controller have a diode and others do not. Maybe your controller is shot. Worth a check.
How is it getting power to work as it should with your battery disconnected?
Some buyers will make multiple accounts and send offers as an attempt to wear you down. If they can’t type a sentence and just send a number I ignore it.
I may have a stock J35 , adapter plate , headers, wire harness, almost new clutch, and honda computer for sale in the spring. I also have an AEM computer for the J35. I’m in Montana and it's too cold to pull out at the moment.
Not the deal of the century but they also have free shipping. Today is the last day.
https://www.aeswave.com/Power-Probe-PPKIT03S-with-PP3CSRED-and-ECT3000-p9910.html