24v hell asap

biged681985

biged681985

Arklahoma Bombers
Joined
Mar 12, 2008
Messages
306
I just built a 24v here at work, got it all put bak in, and the truck started right up.

now for the problem

the alt wont charge, and if you rev the motor to 1500 or above, the gauge drops to 8. check the batterys, and it shows its 12v. turn the key off, and right back on, the gauge goes back to working. the abs and the airbag light is also on. ive looked every where under the hood, can find no loose wires. no borken wires, if done a self test on gauge cluster, changed gauge clusters, tried a different PCM. checked all fuses, checked all fuses, and checked all fuses again. i need to get this figured out asap

but other than that, the truck sounds perfect
 
ive checked all the grounds that i can think of, all are hooked up and got a good connection
 
[ame="http://www.youtube.com/watch?v=7j84KwvNReU"]http://www.youtube.com/watch?v=7j84KwvNReU[/ame]
 
Please do this. Hook and wire from the blue wire at the back of the alt and hook it up directly to positive battery. If it charges then you have a break in the ground wire somewhere. Mine is broken and i couldn't track it down. This gets over looked a BUNCH. The green wire is the ground that is contolled by the ECM regulator. You can hook power to the blue wire permintly if it in fact does start charging when you do this.

Sent from my ADR6400L using Tapatalk
 
if the voltage drops as ya rev it make sure the belt is not slipping..and i hate to even mention..routed right so its not running backwards....its been done..jus sayin
 
no codes. belt is routed right. its an 02 model. ill try hot wiring it and see if it charges then.
 
Last edited:
dieselbeef said:
if the voltage drops as ya rev it make sure the belt is not slipping..and i hate to even mention..routed right so its not running backwards....its been done..jus sayin
Click to expand...

did you watch the vid. the alt. doesnt charge at all, the gauge stays at 12v. when you rev the motor, the gauge will drop to 8v ut the batterys are still at 12v
 
biged681985 said:
no codes. belt is routed right. its an 02 model. ill try hot wiring it and see if it charges then.
Click to expand...

Like I said put the blue wire to positive hot. If it starts charging then you have a broken hot wire which is the blue wire. If it does not charge then it's a sensor telling the pcm not to regulate geound. The pcm controls charge by regulating ground on these, not the positive side. The blue power wire goes from the alt, infront of the motor over to the fuse box by the drivers side battery, then over to the pcm on the firewall. I ended up taking this wire completely out and running it straight to a keyed hot wire then directly to the pcm.

Sent from my ADR6400L using Tapatalk
 
sorry for my bad spelling above was on my phone. if you take power to the blue wire and it starts charging that means you have a brake some where in the blue wire which is the hot side of the alt. if you put power there and it doesnt charge, 2 things.

1- alt may be bad. while you have power on the blue wire, take a ground wire and put a splice connector on the green wire and touch ground to the green wire. your alt should go to max charge which is 18v. just touch it for a quick sec to make sure the alt is in fact good and it does charge

2- if you do the above and it does not charge, bad alt. get a new one

3- if you do put power to the blue wire and dont get a charge, but then put ground to the green at the same time and the alt charges then that means you either have a broken green ground somewhere, a sensor is telling your pcm not to regulate the ground or apply ground, check your sensors, or your pcm voltage regulator went out. hope this helps.
 
Hooked a jumper wire up to the alt and it started charging like it's supposed to. Raced to power wire all the way back to the PCM and it ohmed out like it's supposed to. So the alt isn't getting power from the PCM. It does regulate like it's supposed to so the ground is working like it's supposed to.
 
biged681985 said:
Hooked a jumper wire up to the alt and it started charging like it's supposed to. Raced to power wire all the way back to the PCM and it ohmed out like it's supposed to. So the alt isn't getting power from the PCM. It does regulate like it's supposed to so the ground is working like it's supposed to.
Click to expand...

then a sensor is telling it not to send power to the alt. could be a bad relay. i cant remember the name of it but theres a stupid relay in the fuse box on the drivers side that the power wire ties into. you have to take the whole damn fuse box apart to get to the bottom of the relays to check the wire there. i said screw it. like i said , you can just use a t tap splice and hook that green wire up to a keyed hot wire and your good to go man. thats what i did. i hunted for 2 weeks trying to figure out why mine wasnt sending power to the alt as well. i just bypassed the pcm all together on the power side and tapped into a keyed hot wire. works like a charm and saved a LOT OF HEADACHE lol. there are like 5 different sensors and relays that tie into the alt. could be a number of things telling the pcm not to send power there.
 
Last edited:
i dont think its gonna be something i can just wire a jumper wire into. i bet what ever reason the pcm isnt sending the alt power is the same reason the air bag, abs, and blower motor isnt working
 
Check the main fuse in the fuse box on the left inner fender well. My 01 was doing the same thing cause fuse blew, I went threw 3 alternators thinkin I was getting bad ones. I think its like a 160 amp but it screws down with 2 phillips heads and is right where the main power comes into the box.

Hope this helps.
 
Also the relay I was talking about was the asd relay auto shut down

Sent from my ADR6400L using Tapatalk
 
it ended up being one of the fuses was missing. since it was missing, i ASSumed it was a spot for a fuse on a gasser that they had labled in there.

i feel like a total dumbass
 
You must log in or register to reply here.
Top