After nearly a month my local Chevy dealer has come to the conclusion that my truck is not charging due to my ecm. Apparently they are getting a varying to no charge signal. They quoted me $2000 to have a new one installed. I don't have that kind of change just laying around at the moment. Is there any way that I can bypass the ecm and set up an external regulator so that my truck will charge until I get the ecm replaced? Any tips/info is greatly appreciated.
Long shot
- Thread starter ryanelwood
- Start date
this doesn't make a damn bit of sense to me, the alternator isn't controlled externally by the ecm. The alternator has a regulator to control voltage output... The ecm has no bearing on the alternators charging ability.
someone correct me if I'm wrong, but i call bs... I would take it to a different dealer.
someone correct me if I'm wrong, but i call bs... I would take it to a different dealer.
2004 lb7
From what I understood is that the ecm controls the alternator. That's what I understood from the dealer, I'm not a guru on these trucks.
From what I understood is that the ecm controls the alternator. That's what I understood from the dealer, I'm not a guru on these trucks.
I had a customer that had the same issue that the dealer said was an ecm, I have seen a lot of weird ecm issues but never that. He sent in his ecm and I tested it on another truck and it worked fine, I sent a new ecm and didn't fix the problem. Well, so not the ecm, so he installed a new alt. and the problem was fixed.
Either it is charging or it is not. The alternator doesn't charge as soon as it spins because of the internal make up of the system. Sometimes you will get a "battery not charging" come across the DIC but that doesn't mean it isn't charging. That means it doesn't get the signal saying that it is. I would have it checked by another reputable shop. Is your battery dying or not holding a charge?
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The alternator is brand new, I even had it tested. My batteries are not being charged at all. The original alternator stopped working due to a short in the circuit. The short was repaired and a new alternator was put in but still have a no charge issue. So from what you guys are telling me is that the ecm has nothing to do with the alternator? I know theirs only 3 wires on the alternator, the b+ , the charge indicator light, and the signal wire that runs to the ecm (please correct me if I'm wrong). What else could it be than? I had Chevy look this truck up and down for 2 weeks on just the no charge issue.
With the short it was possible that it hurt something in the ECM but that probably would not make the batteries not charge. I would think that another ECM could be gotten cheaper than that but the dealer is going to get you at full retail plus their labor charges. I will try to check tomorrow with a good friend about your problem. What year truck are we talking about? Maybe your short is not fully repaired also.
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Make sure the nut on the jump box is tight on the positive wire. Its that red box infront of the upper radiator hose with the "ground" sticking off it. If thats loose or anything else like that every (like 30 seconds depending on continewity(go ahead and lol at the spelling)) you'd see the voltage gauge drop and get the battery not charging DIC. Also FWIW if it was the ecm (which I agree with everyone else) you could do that yourself in 5 mins to save alot of change. Check all your grounds and connectors
ok man pull up the plastic around the fuse block.
under it is a big megafuse that blows when the glow plugs or intake air heater is shorted.
Find the short that is blowing it and replace it
The alternator charges through that fuse man.
Dealer techs these days..........:thumb:
under it is a big megafuse that blows when the glow plugs or intake air heater is shorted.
Find the short that is blowing it and replace it
The alternator charges through that fuse man.
Dealer techs these days..........:thumb:
Its a 2004 LB7, yea any information I can get is greatly appreciated. I will be rechecking everything that I've already checked, very possible I could have missed something simple. I did check that nut in the jump box to see if it was tight and it was. But I never took it off, if it were corroded on the backside would that cause this issue?
Just stick a test light on the b+ stud on the alternator, if it lights up bright then you have power there.:thumb::thumb:
I actually just had the whole fuse box replaced so I hope they would have seen a blown mega fuse when they did that...
Not likely to corrode there and cause that problem. Check the jumper tab that makes the connection there to see if it has broken there. The fuse is a great place to look. You have to pull the plastic housing off the fuse block to find it.
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