Brand new alt checked good but no charge

[Strokergonebroke]

99 psd

Brand new alt got it tested and it tested good. Batteries all tested good.

Fuses all good.

When volt meter is on prong on alt it reads nothing but olhms, all grounds are connected also.

Any ideas guys?

[gomer pyle]

what kind of volt meter? what setting are you on? start your truck and turn headlights, heater, etc. on and check voltage at battery. it should read 14.0+. if not then it could be voltage regulator

[Strokergonebroke]

We tried a auto reading and selectable.

Batteries dont read 13v. 12.8v once i jump his truck and slowly die, disconnect both batts and trucks dies.

Plug going to alt reads 12+ volts.

Could the relat switch on the passenger side be dead or not working? Truck starts perfect when i jump it due to batts being stupid low.

We just put a new engine in and this problem is all that stopping us from celebrating haha

[gomer pyle]

sounds like voltage relay is not telling the alternator to charge.

[Strokergonebroke]

Were is this located at? Is this the pod that looks just like the glow plug relay

[hydroman]

Who/how did they test the batteries. Most auto parts stores don't have a big enough "load" to check the batteries, need about 300 A.Also are you getting exicter input to the ALT? Not familier with these alternators so I don't know if the REG/EXCE is all internally controled or not but it does need a source from the battery just the same
Mike

[gomer pyle]

Not sure where it is located, it could be internal or external. The problem has to be with the alternator because you don't have the right voltage with the truck running

[ZMANN]

it sure sounds like the + lead from the battery to the alternator has an issue from your description ?

it should read battery voltage at both ends so you seem to state it doesn't read any voltage at the alt end of the battery lead ?

[ZMANN]

I know this site can be cheesy but as I was looking for a diagram for you I found this

batteyr light came..my 1999..battery light does not come..cables - JustAnswer

[Strokergonebroke]

I found the problem. My dummy friend put the cable on the wrong side of the starter relay so it only worked when we were starting it.