i have a problem with my charging system... voltage reg works then doesn't... output goes from 14 to 11 or less with lights or other items on. must be bad ground or loose wire. ??? where do i start looking first? second?? thanks in advance!!!!! alternator has less than 5000 on it sometimes if i hit a bump all is fine

Well, if it goes to normal when you hit a bump then your components are likely working correctly and your circuit is having issues. You need to check you circuit board, plugs, connections, wires all one by one and see if you find any in disrepair. Your alt will put out 14 just fine, if when you put on lights and such it drops then your regulator is out of the circuit due to its connection or other malfunciton concerning it. Its sole job is to keep the to voltage at the battery semi constant to cope with heavy draw or lack there of.

Definetly check your circuit board. It could have a corroded run in the regulator circuit.

I agree with the Dr, and also as I did for years at GM dealerships. Run the circuits which is your case is to run the engine with or without heavy electric loads and move the harnesses around. Keeping an eye on the volt meter. Keep tabs on each section as you move along. Surely make note of any groups or single wires which feel warm/hot as thats a good sign of a poor quality circuit/connection. Be patient and keep alert to any changes in the engine idle speed or the typical sound of an alternators output which is a slightly high pitch electromagnetic wine. That may pop up between views of the volt meter.

shorted plates in the battery can cause this effect also. try another battery.