battery light on?

[ronnny]

The battery light in the dash is on. I was going to swap the altenator between my 2 trucks but found a wire on the back loose. It goes to the connection marked "E". On the other one it was connected to ground on the body. If i connect this wire and start the truck it will melt this wire like a fusable link. It charges normal and runs great just the light is on and brighter when the motor turns faster. Is this just in the rectifer inside the altenator? What else would it be. The altenator is putting out 14 volts slightly above idle and a little less at idle. The only thing wrong is this wire and the light.

[fastdadd]

mine does the samething...turns out it was the fuse for the dash lights burnt out...check there

[ronnny]

My dash lights work fine though? But yes i will look.

[datzenmike]

ronny, I had to look up all your old posts to find what vehicle you have. Now I may have read this before but I getting old and can't remember everything. Also, others might have a suggestion but without knowing if it's an internally or externally regulated alternator or the year so they can look up the wiring diagram they may be hesitant to help. Help an old guy out and complete your signature so we can refresh our memories on every post.

 

Now I've forgotten what I looked up.... Oh yeah, '82 720. The E terminal should have a Black wire on it that goes to Ground or the negative side of the battery. It's probably grounded to the alternator case as well. The other terminal should have a large thick possibly double White wire that goes to the fusible links and through them to the positive battery post.

 

The ground wire should not melt like that. What size wire are you using for it. It should be fairly thick like 12 or maybe 10 gauge. If the burning wire and charge light persists, swap with a known good alt. If the problems goes away then this alternator is bad.

[ronnny]

Ok will fill out the profile in a few minute while i am thinking about it.

 

On the altenator there is 3 connections. 1 is a plug containing two wires. A 2nd has a "B" That is a bigger wire that goes to the battery. Not sure if there is a fusable link there or not. The 3rd connection is the one marked "E" that had about a number 16 wire black coming off of it going nowhere and do not see where it went. When hook it to the body it burns when truck is started (on the 84 where the light stays on). On my 82 this someone put a #10 wire grounding to the body.

 

My plan is to take the altenator off of the 82 i do not drive no more and put it on the 84 to see if this gets the light to go out and hook up the ground wire. The 82 is not going back on the road but i want to keep it running because it is a good running motor and tranny. So the battery light staying on will not bother that truck. Just have to see if tomorrow or this weekend is good to do it. Was just messing with this today since changing the belt that was going bad.

[OL YELLER]

May be wrong...but I seem to remember that anything marked "E" would be earth or ground wire.

[ppeters914]

May be wrong...but I seem to remember that anything marked "E" would be earth or ground wire.

 

No, you're correct. I'd say take both alternators and have 'em tested, but the one that's frying wires when you connect the E wire to the body/frame definitely has a problem.

[ronnny]

Ok i changed the alt. and at least got the one from my 82 onto the 84. The light went out and no wires burned up. Once you start on this it is a pain with the ac and radiator hoses. easier ro take out the battery to get to the mounting bolts and a way to get the alt in and out passed the hoses. But the light did go out when started the truck back up and there is 2 wires going to the "B" terminal and a black wire going to the "E" that may be a number 10. There is also a little capacitor looking thing bolted there but no wires to it. Then the other 2 wire plug in. Ran good up and down the road. Later this week put the other in the 82 and see if its light comes on. It did not have one of those capacitor looking things on it though. If it is still charging and gets me to work tonight and home in the am i will be happy. I just have to start on gettin' rid of some pollution stuff next. thanks for the help and insight on this yall.