Hey guys i always like coming to yall since you're a wealth of knowledge. so the main issue im having is that it feels like im not getting enough power from my alt. the alternator is like only a few months old and is my third in just as many years. the alts check good but i don't get enough power. i swapped my old red top with a yellow top about 8 months ago. if i don't start the car every few days the battery is dead. so i guess thers a draw somewhere. next when i brake the heater, dash, and headlights dim down. my defi gauges reset. when i installed them i read how to do it from here but i used vampire clips from the radio harness. ive read on here that it might be the grounds. im the 3rd owner so theres hella stuff thats been done and disconnected wires in the engine bay which i hate. I have one of those sexy style hoods so i wonder if the elements kill my alt? i dont know guys u really need help on the correct course of actions. t hanks in advance

 

Not much of an electrical guru, but if your battery is going dead after sitting a few days,
it certainly isn't the alternator.
Get a MM and with the engine running, see how many volts are going back into the
battery. If >14 alt good. I would use the MM, remove neg bat cable, mm positive lead to
cable, negative lead to battery post, set on amps and check for draw. If high, go fuse by
fuse until draw found.

 

Year of the car? Are you using an S4 or S5 alternator?

 

i have an 89 t2 and im using an alternator for it. I just dont know why all lights dim when i brake. at a light i feather the accelerator to make sure it doesnt die. when the revs are high all lights are nice and bright

 

What is your idle speed? The belt could be slipping.

You can measure the output of the alternator at the large cable connected/bolted to it and it should read 14 volts when idling.

The S5 alternator has a plug w/2 wires. One of these wires runs to constant power so it would be easy to check. If this wire is not wired properly it causes the battery to drain.

A bad alternator will drain the battery. If the battery is properly charged and you disconnect the bolted output wire of the alternator and the car starts after sitting a period of days then the alternator is likely draining the battery.

You could also have a voltage draw which you could test for.

 

You need a multimeter to diagnose these issues,not really something anyone else could diagnose otherwise,my lights also dim when I have lights and everything on and tap on the brakes,although my
natyer and alternator are both very old and I don't have any of the emissions(idle control valve).
I have a parasitic draw in my car,I haven't gone through it yer because it's parked for the winter