RED RUNS a little hot and and sits right on 18 volts i thought the alt belt wasnt tight and so i pulled it apart and tightened it up but i still is doing the same also my amp for my 8s is not puting out base a it should it seems to put out when the car is stoped but as you give it gas the base wont hit as hard i thought the belt wasnt tight eff but i got that bastered thight now and its still doing it anyone had this problem befor or no how to fix it ................also to any one who owns a Ttop car dont drop your ttop.............. wind is not your friend

 

you have a problem with the alternator if it sets on 18 volts. The amp is supposed to run in the range of 10v to 14v. The alt should put out 14-15v max. Those alternators are internally regulated so basically you need to replace it! Dang that car has some problems.... hold onto those T-tops!

When the car is turned off, but the ignition is still on, does the voltage needle rest down by 14v or 12v? it should. Should read 14v after you've had the car running. A while later it should rest on 12v. If not, then the gauge could be bad but that doesn't usually happen.