07 Suburban with approx 115k

I recently noticed my dash, tail, DRL & marker lights pulsing when at idle. I also noticed my engine running rough at the same time and all this happens only when during an idle. The odd part is I never notice my voltage Gauge Float into a conserve mode until this pulsing & rough idle has begun to occur. The gauge was always at a low 14v whenever i would look at it. Now it does the float thing controlled by the computer.

Things to know... I have a new battery put in about 6 months ago cause the last one simply died. No issues once installed for a about 3-4 months. Also I did install a new headlamp set with some leds in it and also added a HID with ballasts for the Lo-Beams. The HID lights are the only thing that runs without pulsing. All other lights pulse whether the HID are on or not. The pulsing started maybe a month or so after the headlamp/HID install.

Maybe there is a diode or resistor I needed to add into the headlamp LED install? Or is it something worse like the computer that regulates the voltage for the alternator? Or possibly the alternator itself?

Thoughts on adding a "Voltage Stabilizer Regulator Grounding Kit"???


thanks for all input and ideas...

Ron

 

whats the voltage at the battery idling? No codes of any kind?

 

depends if its in conserve mode or not. Starts at a low 14v and if there is no demand then drops to high 12-13 and will jump back to a low 14 when needed. Battery is an Interstate and its actually 1 yr old (I got confused with my other car).