Expert: Robert Summers - 10/29/2008

Question
My question is I had an other motor install in my truck and new alternator and new battery, and when I put my a/c on the amps go 2 lines under 14, I was told need more ground

Answer
Hi Raul.... when you turn on the ac the rpm drops that will be why your alt volts also drops...use a voltmeter see what you have for volts before you turn on A/C and then after...you may need to bump the idle a bit ... idle drop is common when you turn on the A/C... if voltage is 13.9 and above at idle when no A/C then you are ok...if below 13.9 with no A/C then you may need to check the alt....and it won't hurt to check to make sure you have good body to engine grounds....hope this helps