Current draw and alternator charging problem

[72Z/28]

Hello guys

I need help to resolve the issue with the current draw and the alternator that seems to be not charging.

My new red top optima battery dies if the car is not driven for a few days. I checked for a current draw using a multimeter, and there was a current draw of 0.12 amp. The reading dropped to zero when I pulled the horn relay from the Painless Wiring fuse panel. The horn relay was tested later and found OK. I wonder what else can cause this current if the horn relay is good?

The other problem is that the alternator (1 wire alternator) is not charging the battery. I am ruling the battery problem out as it is always hooked up to a CTEK charger. The voltage is 12.6 when the engine is not running. According to Optima the maximum voltage on Red Top Batteries is 12.85V. With the engine running, the voltage barely increases to reach 13V and it drops to below 12.6V reaching 12.2V when the engine reaches operating temperature. The voltage reached even below 12V when the alternator was on load, AC running and headlights on. At 2000rpm, the voltage on the multimeter was fluctuating between 12.7 and 13.01V. Also, the turn signals blink for a few mintues then stop blinking.

Is this an indication of a bad alternator or is it the ECU that is not giving a command to the alternator to charge the battery? The alternator is off a 2002 C5 corvette. The plug connector at the alternator has 3 wires,one of which is connected.

Guys your input is highly appreciated.