Voltage spike when on the gas....
 

Alright, so I was driving the rig around tonight and while in traffic, I noticed a spike in voltage when I was on the gas. I was in stop and go traffic, so I could really see it happening on the dash. My dash lights also got significantly brighter when I was on the gas. Is this normal? I have just replaced the battery, so I'm pretty sure that it's pretty good, and based on the fact that the voltage increases when I'm on the gas, I don't think it's the alternator. Any ideas? Thanks!

look for corroded grounds or check the resistance of your system

mine does that too, let me know if you find out.

With your lights dimming you are seeing the difference between the 12 volts your battery puts out and the voltage your alternator puts out (Usually about 2.5 volts more). If you got any extra electrical equipment the toyota alternator gets swamped pretty quick.

If your truck is older corrosion would have started rearing its ugly head making the situation worse just like youngyota88 said.

Putting heavier gauge wiring will help a bit.

It done died!
 

Here'a an update... I was pulling into my garage, and it died. And it died hard. I pulled out my alternator, as that was the logical thing to do (or so I thought). That tested fine. The connection was a bit corroded at the alternator, but I'm not so sure that was completely the cause. Any bright ideas before I go and stick the alternator back in the beast? Thanks!

voltage regulator? Fusible Link? Charge fuse?

I had a voltage regulator go out on my alternator and caused the blowing of several sets of headlights in the middle of the night!!!!!:( I think that even if the alternator tests good the voltage regulator could be messing up and not all the time. My headlights would blow at random times until i got the alternator replaced.

I checked all the fuses inside the truck, all looked fine. I'm not sure where to find the fusible link, can someone point me to that? Thanks.... I'm only slightly better than retarded when it comes to this stuff....