The other day I started my truck and everything was normal. As soon as I disengaged the parking brake the voltage gauge dropped down to 9. I have been having this problem before when it is cold outside and it usually gets back to normal after a few minutes. After it didn't correct for 30 minutes I turned the truck off and tried to restart it. It tried to turnover once then it started clicking. Could this be a problem with my starter or alternator, or both. Also the voltage surges regularly, not sure if that could provide any answers.

Thanks

 

I doubt it is a starter problem. First clean and make sure the battery post are tight. The alternator may not be charging the battery. I suggest you check the battery voltage with a voltmeter then jump start the truck and check the voltage across the battery again. The charging voltage should be at least a volt or more higher with the engine running. Normally a good battery will measure above 12.6 volts and with the engine running it should be about 14 to 14.5volts.