i used the 98 alt and took it apart and swapped the rear section so the 3.0 harness would plug directly in. i dont think it is charging b/c my battery kept going dead.

i jumped it off and checked the voltages at the round plug. the red wire and white wire have 12v but the yel/blue does not have anything. from looking at the wiring diagrams it looks like this should be getting 12V from the dash indicator. is that correct? just hoping to narrow down what i need to search for

 

Why don't you put an meter on the battery cable and find out for sure if it's charging or not.

 

I just got my swap running so I haven't had a chance, but I'll throw some voltmeter leads on there tonight and see if the alternator is charging the battery.

 

ok got a little more info. there is 12v at the 7.5A CHARGE fuse. the bulb on the dash does not light up when the key is turned on. pulled the cluster and there is 12v on both sides of the bulb (meaning the bulb has power but no ground to make it light up) swapped it with a known working bulb just for the heck of it and it still does not turn on. from what my wiring diagram shows if i have power at the fuse it should be getting power to the alternator yel/blue wire.

any ideas?

 

I know you already swapped the back thing but can you replace the stock one and just splice on the newer connector on to it. Should match up color for color.

 

i can swap it out. i think it is a problem with the alternator itself. i am going to try to ground the yel/blue wire tomorrow and see if the dash light comes on. if it does then i know the alternator is not grounding the wire like it should

 

I guess also make sure all your engine block grounds are good. Hope it's an easy fix.

 

is the alternator suppose to have a ground wire or does it ground through the bracket? as far as i know i only have one engine ground from the negative terminal on the battery

 

On the 3.4L, there should be a ground strap from the back of the passenger side head to the firewall. Another two eyelets attach just forward and below where the diagnostic box attaches to the upper intake manifold on the driver side, at least in the original configuration.

 

Grounds thru bracket but you should have grounds from battery to block and battery to frame/sheet metal too. I don't know if that makes a difference in this case. There should be plenty of grounds between everything.

 

the only grounds i have are battery to block and then battery to body just beside the battery post. i will add a couple of engine to body grounds and see what happens

 

i think the 2 eyelets are attached in the manifold. they are all brown wires i think. i will get the head ground attached tomorrow.

 

It sounds like your grounds aren't the problem if you have at least 1 ground from battery to block and body. I was merely suggesting that you make sure the grounds were there and of decent quality. Let us know after you do your testing tomorrow.

 

i checked today by grounding the yel/blue wire and the dash light comes on. could have saved time yesterday by doing that vs pulling the cluster!!!

so it looks like the alternator is the problem. i am swapping it out for a new one tomorrow and am going to just rewire the plug to use the 98 alternator harness.

 

Just a quick check but at idle I'm getting 13 volts at the battery so it does look like swapping the rear plug and the heat sink does work.

 

Good info ultimase. You should update your build thread post regarding that info too, for future searchers.

BTW I think you should have run her up to about 4 grand open dump headers to check voltage for us

 

No more open dump... kinda eerie but it's actually pretty quiet.

I'll update the build thread and the alternator thread when I confirm and also load the alternator up.

 

the alternator was bad. got a new 3.4 one on there and swapped the old plug to the new 3.4 style one and it is sitting pretty at 14V now. also got a new battery just to be on the safe side