Apr 27

Troubleshooting voltage drop

1994 Mustang 5.0L, TRS Mini H1 Stage III: 5.0 projectors, 9007/9004 Motocontrol Bi-Xenon wire harness, and 3five DSP ballast with xb35 5500 bulbs.
Also running XBLed fog lights, but rarely use them.

Having an issue with voltage and RPM drop when headlights are initially turned on. Normal start and warm up, no problems when turn on corner/turn signal lights. Once I turn on my headlights the voltage will drop around 4-5 volts and RPMs drop around 200-300 RPMs. Bulbs do not flicker and warm up normal.

Upgraded all grounds with 4AWG fine stand speaker wire, cleaned all TRS harness grounds and power connections. Upgraded stock 130amp alternator to 200amp and running Optima red top battery (both tested good). As well as replaced headlight switch, wiring harness and fuses.

Done everything I could think of and cleaned everything possible but problem still exists. Could this be an issue with the motocontrol or ballasts?