I'm not sure how thoroughly you followed the wires to and from the alternator, but check all of them, and make sure they are all good, and have good connections. I guess it is possible that water got in somewhere and as soon as current was run through it, it shorted out. That said, i would invest in a multimeter, they are like $10, that way you could figure out for sure if its the alternator or not.

 

I'm suprised no one has told you yet. It's an alternator, not a generator. You need the battery hooked up to excite the windings to create electricity. It will not run with the battery disconnected. At the same time, if you disconnect the battery while the engine is running, you'll most likely burn up your new alternator.
You need to get your wiring back in order, put in a new or at least, tested and confirmed operational, alternator and quit pulling the battery cable while it's running.
Good luck.

 

actually, it will run off the alternator once the engine has started.
it has two connections to the battery- one for the windings, the other for the regulator. once the engine has started and the alternator is producing current, it will self-excite the field windings and regulator. and that's one reason it's not recommended to do so- it can cause the system voltage to climb too high.


87yoda87- there are a couple of fuses for the alternator so make sure they are all good- in particular the 'charge' fuse, which I believe is a 7.5 amp

 

im having about the same problem in my 94 toyota pick up. When ever i turn some thing on real quick like the bright light or fan motor it makes my truck skip. when i turn the turn signal or some thing on the truck will skip to the turn signal.I took the truck up to the alternator shop and he said there was nothing wrong with altenator.Does any one have any ideas that could be causing it. i done put new wires plugs distrubture cap and button. new batterie new terminals and none of it helped.

 

if your not going to use your 87 alt bracket I want it

 

Ok I got this problem where at night my lights and everything pulsates as im driving..never really when I stop. The volts gauge moves with it. So im guessing that the regulator is going bad since when the charge/ebrake light comes on and I disconnect the battery the truck still runs. So since the regulator is built in I need a new alternator.

Just want some other opinions. And it only does this every so often.

 

i dunno man. honestly, only real way is to test it and find out. That said, these are old trucks, chaffing can happen, ground faults, fuses and messed up fuse boxes. i mean, i don't mean to sound like a crazy man, may just be something simple, but, when it got humid, the current running through the pickup just started to go around and cause funny things, like popping fuses and creating dimmers for the lights when it felt like it.(massive run on sentence)

Honestly though, its always a better idea to test something before the replacing of parts just starts to happen. voltmeter to the rescue

 

Yeah could be a number of things. But I just wanted some opinions to see what I should check out the change it. IDK the last time this alt was replaced.

 

Ok so now the lights came on just driving down the road with only the stereo going. I drove it to work like that and when I got there I disconected the battery with it running and nothing happened. So that rulled out a bad alt. But ill check the voltage output pre start and then started at the battery. im guessing its the voltage regulator. But when I was off work and started my truck my volts gauge was pegged out at 18volts. I reved it and the charge light blinked then the voltage dropped down to where it normally is...then about 10 mins down the road both lights came back on....but when the lights come on my volts gauge doesnt change.

Regulator?

 

you don't test it by pulling the positive cable you fry things that way you test it with a voltage meter.

 

first off you don't test alternators by disconnecting the battery while its running you will fry things. use a voltage meter while the engine is running.how old is the battery? even new they could be bad. p.s disconnecting the battery causes a voltage surge through the system that is not filtered by the battery