1988 Toyota Supra Control Module

[fpoli75490]

Hi,
I have a 1988 Toyota Supra manual (non-turbo). 6 months ago my car didn't start. The battery was fine. There was simply no engine sound, no huffing, nothing. My mechanic let it ride down the hill and while rolling he was able to start the car. Subsequently, he said that in the cold weather there may have been built up moisture in the control module. He said I was missing the "negative" from the control module to the relay starter. He then unplugged the control module and plugged it back and it started up fine. Now, my car won't start again and my battery is fine.

Can anyone tell me if I should unplug the control module like the mechanic did? If so, can someone tell me where the control module is? Or does anyone have any thoughts on what I should do?