Hey guys, well here is the story. I had the original alternator with about 120k miles and it wasnt charging the best but still holding some charge. So i figure get a new one before it dies one day going down the road. Get new alternator due to the fact my old one was unrebuildable (According to experts) and i had to go out of town. Well step dad needed truck so i told him to hook new alternator up (thinking he could do it being semi mechanical) no, he hooks it up with the batteries on and left it here for me. So i get home call the alternator guys and they say check fuses and replace the ones that are bad. So i did, replaced one 10amp under the hood and none by the steering column. Now I jump in truck and wait to start light comes on and battery light as well as abs light ( abs brake never came on) and start it. About 5 seconds later i realize starter is still engaged and the gauges and lights all die, but truck stays running. so i quick shut truck off look at starter cylinoid and all the wires are fine and tap starter thinking it was stuck try it again, same problem. Sorry this is so long. Any help that would be great Thanks.

 

I've changed lots of alternators with the batteries connected. One just has to be careful not to short out the alternator output to ground. I always remove it first then tape it up. As far as starter staying engaged make sure batteries are fully charged and retry.

 

so if batteries arent fully charged the starter will stay engaged? i guess im confused to why the tachs arent working

 

theres a 5 or 10 amp fuse under the panel that powers the dash and gauges, that could have popped. if the ONLY gauge that is not working is the tach and it wont start still, could be coincidentally you CPS ate it at the same time...but that probably isnt likley

 

Starter staying engaged is a low battery charge thing.

The dash gauges are 5 amp i believe.
And the 4amp in there, i cannot remember what that one does, but it is easy to go, or break even if you remove it. I removed mine and it broke.

 

Thanks so much guys, but how come after the truck is running for alittle bit it just dies? its almost like the new alternator isnt doing anything, should i maybe get new Batteries?

 

if they are over 3 years old, they are probably not so great.

It shoudln't die though after it starts, its the alternators job to keep it running.

 

batteries were replace this past summer. Its weird i went out to start everything worked until i took the charger off the battery and then guages failed and shortly after truck just died. its like the alternator isnt working at all.

 

Probably is not then.

Check the main wire going to it andm ake sure the connector is good and not broke or screwed up.
Everyone always puts them on upside down and when you lay on them, they get messed up.

 

well guys, new update.. Got new solenoid just for safety, tapped started then started truck same problem starter stayed engaged. Next i unhook alternator and start it everything was fine, just the fact im running off of batteries. Next i hook it back up and leave the little greyish white clip unplugged. same problem. next unhook the black plug on top of alternator and the starter was fine, just wasnt charging the truck. Next i started truck with black plug unhooked and then plug it in while truck is running and starter doesnt engage and runs fine, still no charge. Any other ideas?