The other night I drove to the farm and all was fine. Let it sit for about 1/2 hour and restarted truck. Check engine light is on and no charging. Code 41 is set. I cleaned connections by alt. Then it worked for a day. Did some research on here. Checked crank sensor. Its ok, besides a/c works when alt doesn't. Tonight it quit working and I tapped on alt case and it took right off. I am wondering if the alt is just tired. I am going to try the asd trick next time it acts up.
Ok so now for the dumb question: Where is the computer on this thing? I kinda thought it was behind glove box, but that's for RWAL?

 

Computer on our trucks is attached to left fender behind the battery.

 

I've got a question...where is the crank sensor+how do I check it?

 

Thanks dodgestien, I will check it out.

The crank sensor is right above the harmonic balancer. It has three wires going to it. As far as testing it I am not sure of a technical way, but... If the alternator, a/c, OD, cruise work, it works.

 

This could be an indication that the brushes are worn and making intermittent contact.
Jim

 

Would it be an ultimate no-no to spray electrical contact cleaner on them?

 

Mine was doing the same as you describe before the alt. went south. Replaced it with a new one and all has been well since.

 

Unless the back of your alternator is covered in oil I don't think that would help, when the brushes wear down the lead wires seem to get hung up on the brush holders and will not allow then to press against the slip ring.

You should be able to get replacement brushes for the ND alternator at the auto parts and they should not be expensive.

Your year is a bit harder to check because of the electronics but if you take the serpentine belt off, start the engine and carefully spin the alternator pulley by hand, if the brushes are good it will be difficult to turn, if it spins freely it could be:

1) The brushes are bad.
2) Regulator is bad.
3) Crank sensor.
Also check the obvious like loose connections on the back of the alternator.

Since it is an intermittent problem this test could also show as a good alternator.
I would simply split the alternator and check the condition visually.

If you have not dismantled an alternator, there is a procedure you need to follow to cage the brushes in the holder before you reassemble it so you do not break them.

This will be in the repair manual and is not complicated; all it requires is usually a paper clip.

Do not let this scare you into checking them though.

Jim

 

Now we are talkin' I would like to just fix the alt I have. O'junky's wants like 130 for a rebuilt.
I have checked the crank sensor.
I also checked and rechecked the wiring. Will check out the asd in the daylight.
Any numbers for the brushes? Is this something NAPA can get?
Can you ground one field terminal to check charging. With engine running one should be 12v and one modulated ground right? Or will this fry it for good?

 

I am not sure on the connections without checking the manual BUT I would not GROUND anything out with the harness connected and take a chance to burn out the computer.

I would have to check for the Full Field procedure on this alternator.

Napa should be able to get the brushes; I get my parts from a local Electric Shop that rebuilds truck electrical parts, starters and alternators.

Jim

 

Just above the crank pulley. Look at the wires, check for broken wires or worn insulation. The gap between the sensor and the damper should be 0.050", check it with a brass or plastic feeler.

 

Follow the harness from the alternator until you come to a harness connector/plug. Disconnect it and put + and - to the two smaller spade connectors that go to the alt, it doesn't matter which order. You will get really great charging (mine went to 17 volts) or your alternator is junk and you can stop looking for other things. -Jim-

 

Ok, I might try that just for fun. I am fairly sure that the brushes are worn. Got a new set comming for around 13 bucks.

 

thanks again Dave.