Alternator Excite

Hi, My alternator was not putting out current and I think traced it to a bad excitation circuit. It is a Volvo MD7A. The alternator is a Valeo (not original) The current from the warning light to the D+ terminal was only about 1 Volt. When I flashed it with 12 volts, it worked and put out 14Volts. I had replaced the warning light a while back and probably put in the wrong type. What should the voltage be from the warning light to the D+ terminal for proper excitation on a regular basis? What happens if I just jumper it out and have 2 volts to the D+ post? As always, thank you in advance for your help. Chris Cal 31 Poulsbo, WA