Driving home 90 mins from the airport, lights seem to be a little dim, then with 30 minutes to go the battery dash light came on (maybe others). Made it home and parked it. Kind of forgot about it as its not my daily driver, but started and moved it around the yard twice without issue. Went to drive it about 2 weeks later and it turned over a bit slower and when putting on lights and defroster the lights were noticably dim. Parked it and replaced the alternator, charged the battery, and thought all was fine.

Its not - the alternator is not charging the battery. It will be dim and continue to run until the battery drains itself. I tried the ELD bypass and it doesn't seem to have any effect. The battery dash light as well as the brake light and all of the door open lights are showing on the dash. The ground cable from battery to down by the engine looks a little frayed, but I tried to bypass it by connecting a jumper cable from neg post to the same spot and no change to the dash lights. There is a single wire with a connector over by the alternator that had a bit of a break in the insulation so I tried to splice that before I replaced the alternator and didn't seem to make any difference.

So if battery and alternator are good, but its not charging, I'm not sure what to test? I brought my old battery to Advance and they tested it and it is showing its still good, so it doesn't seem that was my original problem. I don't think its ECU as the car runs fine, but I need some kind of troubleshooting guide. Any help appreciated.

PS Car has been in family since new, has 319k on it

 

Check driver's side under-dash Fuse No. 6 (15A). That fuse and the Blk/Yel (IG) wire supplies the ignition input that turns on the alternator/regulator assembly.

 

Additionally it may be the ELDU.

 

Checked fuse and was OK.
I have batt voltage at the black/yellow wire as measured at the 4 pin plug at the alternator. Charging light also stays on as noted above.

I tried to bypass the ELD using a 1k and 4.7k ohm resistor as mentioned elsewhere and didn't seem to do anything.

I thought I had read cutting one of the 4 wires going to alternator would force it into full charge all the time but set an SES. I'd be ok with that as long as it wouldn't burn anything up..

Anyone know whether that single wire I mentioned could be a trouble spot and/or whether my "test" to bypass the ground strap that seems a little frayed proves that is not an issue?

 

Check the harmonic balancer rubber bushing between outer pulley and inner drive. A loose, worn bushing will cause very unusual charging problems; sometimes no light but low charging and discharging when headlights are on.

Sometimes it is visibly loose, others it slips under load. Make a radial mark across outer pulley, bushing, and inner drive. Run the engine and see if there's any slippage indicated by circumferential displacement of part of radial mark.

good luck

 

Hmm, will try to check that tonight. Would not seem to be the issue, as even when volts were down around 10 and it was stumbling, it wasn't putting out anything (i.e voltage on the back was equal to battery voltage). And initial issues showed up while driving down highway. But I'm out of ideas so what do I know

 

With the battery fully charged and the alternator wiring disconnected, have your started the car to test if the alternator is working. If it is in fact good (albeit a new rebuild) then it is time to start chasing wires as there may be a break in connectivity (literally a break or excessive corrosion which will show a green oxidized color) or a wire is making ground where it is not supposed to. I am not exactly sure about your process for bypassing he ELDU as a straight wire bolted onto the contacts usually does the trick for ruling it out.

 

When you say alternator wiring disconnected, do you mean pulling the 4 pin plug on the top? No, I have not started the car with that unplugged.

As far as bypassing ELD, I removed the plug and stuck in the resistors as I noted in initial post. Though my are 1/2 watt and weren't nearly as thick as the one shown here so perhaps it wasn't making contact like it should have I suppose. Will try again to be sure.

Does anyone have a Honda service manual that shows a troubleshooting flow? I only have a Haynes for the car, and its obviously useless in that regard.

And though I had my old alternator tested off the car, I haven't had the "new/rebuilt" one tested to make sure its good, but I figured it wasn't worth it since the light showed up with the old "good alternator so its a car/wiring problem, not the alternator. I'd put the old one back in to avoid that as a variable except the idiot at Advance Auto DROPPED IT when he took it into the back to test it. Thought I heard something but wasn't positive. Didn't notice until later when I got home that it cracked the case.

 

Suggest investing in a download emanual from automanualsource.com for $22.

Also, a battery monitor such as follows is handy to see what battery voltage is doing all the time. $15 at Walmart.

Equus Innova 3721 Battery and Charging System Monitor - Walmart.com

good luck

 

Just found the supplement manual for 98-01 Accord V6 online, score! Will go through these tests tonight, fingers crossed!
Link to supplement