RTH Electrical Problems

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96Cruiser13

96Cruiser13

10 Year 15 Year
Joined
Jul 11, 2007
Threads
70
Messages
1,693
Location
Burlington NC
At 155k, my rig wont start unless i jump start it, but when i jump start it, it will run for approx. 1 minute before the voltage slowly drops and it bogs down. I held my multimeter on the battery after jump starting the car, and it jumped around from 14v to 10v randomly, and then dropped down in ~.3v increments until it got low enough to turn off.
I cant figure out if its the battery or the alternator. Any suggestions???:crybaby:

I topped off the battery with distilled water, and replaced the brushes in the alternator. I'm not trying to buy an alternator if i dont HAVE to..
Any help is MUCH appreciated
 
What is your voltage once the truck is jump started? ASSUMING its only either the battery or the alternator and not some other issue, I would be forced to point to the alternator. The battery is there to start the truck. The alternator then supplies all vehicle electrical requirements AND charges the battery.
 
the voltage first reads 14v, but it jumps around alot.
 
Ok, i was just outside messing with my multimeter, and noticed that when the key is in the ignition, with the door open, the voltage goes down slowly, if i turn more things on (lights), then the V's drop even faster, But when i take the key out and shut the door and everything is off, the voltage goes back up to 11.28v.
 
i just cut into the wire coming out of the alternator that goes into the relays, because that connection was bad initially, and it seemed to have oil on the actual wires inside the heatwrap. Thats not normal is it?

Thia wire :IH8MUD.com Forum - View Single Post - Real time help
 
Just got home from work... just wondering about the oily wires..
Any suggestions?
 
96Cruiser13 said:
Thats not normal is it?
Click to expand...

No. There have been a couple of trucks where the white wire going from the alternator to the battery has a bad connection. That same wire powers the ECU and goes to the fuse box under the bonnet. If there is a bad connection in that circuit your truck will not run on its own.

I think it is called terminal B and there are several threads that will give you more information.

-B-
 
Beowulf said:
No. There have been a couple of trucks where the white wire going from the alternator to the battery has a bad connection. That same wire powers the ECU and goes to the fuse box under the bonnet. If there is a bad connection in that circuit your truck will not run on its own.

I think it is called terminal B and there are several threads that will give you more information.

-B-
Click to expand...

Thanks Beo.
I took the electrical tape off starting at the alternator but only got about a foot before i realized i cant see anything in the dark. With the flashlight i had, So far the wires are fine.
Is there anything else it could be? All my grounds are good. I can take the alternator out and take it to advanced to have them check it, Right?
 
Last edited:
96Cruiser13 said:
Is there anything else it could be? All my grounds are good. I can take the alternator out and take it to advanced to have them check it, Right?
Click to expand...

There are several things it could be. Check the fusible links at the battery and the connections in the AM1 splice point.

You can take the alternator out but it is not a simple unbolt. It is easier if you remove the battery and box. Take it to a good alternator shop for testing.

-B-
 
Beowulf said:
You can take the alternator out but it is not a simple unbolt. It is easier if you remove the battery and box. Take it to a good alternator shop for testing.

-B-
Click to expand...

I took the alternator out the other day, changed the brushes in them and reinstalled it hoping for results. I'll get under the hood at some point today to look at her. Now that i think of it, The 50amp AM1 fuse looked like it may have been blown. I'll update asap Thanks alot Beo.
 
If you need another 50A AM1 fuse, they are around $11 from your local dealer. I have an extra one sitting in the empty spot next to the original.
 
Lka1988 said:
If you need another 50A AM1 fuse, they are around $11 from your local dealer. I have an extra one sitting in the empty spot next to the original.
Click to expand...

Could that one fuse be causing my symptoms??
And can i ONLY get it at a yota dealership?
 
96Cruiser13 said:
Could that one fuse be causing my symptoms??
Click to expand...

Could be. But, knowing that you left your truck in water for some time, there's probably a whole lot of other problems than that.

And can i ONLY get it at a yota dealership?
Click to expand...

Most likely. Or CDan. Cheaper from the local dealer though, cause they don't charge shipping.
 
Lka1988 said:
Could be. But, knowing that you left your truck in water for some time, there's probably a whole lot of other problems than that.
Click to expand...

haha, you guys remember everything :D
I'm going up to the dealership today to get that fuse Hope it solves my problem..
 
96Cruiser13 said:
haha, you guys remember everything :D
I'm going up to the dealership today to get that fuse Hope it solves my problem..
Click to expand...

Not open on sunday :mad:.. Or tomorrow. Terrible timing...
 
For what it’s worth, you can temporarily use a piece of primary wire to replace the fusible link. On a 1997 which is probably the same as a 1996 the charging fusible link wire from AM1 to the battery positive is 2.0 MM² which in AWG terms is size 14 wire. The difference between fusible link wire and regular primary wire is the outside coating. Fusible link wire has a coating that does not easily burn so the copper burns internally without shorting to something else. Just make sure the length is the same.
Internet diagnosis is tough. From post #1 voltage jumping from 14v to 10v randomly I would suspect the alternator.
A farmer way to check the battery is disconnect the cruiser positive and negative battery cables, jump the cables, and run it with a good battery You could pull up the vehicle you used to jump it with before and with the donor vehicle not running, jump start the cruiser. You may want to disconnect the donor’s battery cables first. Check the voltage again with your meter just after you start it and see if it fluctuates between 14v and 10v. If it does this should eliminate the cruiser battery being bad (internally shorted). 10 volts should never happen.

Bill
 
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