whyverne14 Posted June 23, 2014 Share Posted June 23, 2014 I've been searching, but I don't know. On the 86 Dolphin, both the charge and brake light came on when I started it. I heard a few clicks. Put a tester on the battery, less than 12 volt. Bad alternator, right? Well I still have the coach battery; no, nothing. Well, I'll plug it in, no, still no power in the back. Managed to get it home, barely. I can't get a cord to it where it is. So I'm thinking about getting a new front battery and running it to a shop. I don't have the time to work on it. I'm just puzzled about the brake idiot light being on and the lack of power in the coach. If you have any thoughts, thanks. Otherwise a successful first trip. We had fun. Still better than that tent in the car crap. HeeHee. Quote Link to comment Share on other sites More sharing options...
fred heath Posted June 23, 2014 Share Posted June 23, 2014 Your vehicle is much newer than mine. Before changing the battery, check that the isolater is still good. On my rig, the alternator output wire goes directly to the isolater. It then gets split to front and coach battery. The fact your charge light is coming on suggests it's the alternator. Best bet is to pull it and have it tested. Also check the tension on the alternator drive belt. It could be slipping. Quote Link to comment Share on other sites More sharing options...
whyverne14 Posted June 23, 2014 Author Share Posted June 23, 2014 (edited) Thanks. Since the battery says it's over 3 years old and I just took it down to nothing, it might be wise to replace it. There was a local mechanic at the campsite who said he would do the alternator today but I didn't want to miss work so I took the chance and barely made it home. And besides I had it in my head that it wasn't the alternator. I just found a post on "open roads" who described the same symptoms and said it was not the alternator, it was the isolater. So I'm thinking if the isolater is that little salt shaker on the firewall there, maybe I should try going around that after I get the new battery. All I need is shore power for this weekend, I got to figure out why that wasn't working. Maybe it tripped a breaker. I'm on that learning curve. Thanks again. And I just found another post on here that said it was the alternator. Well full test on alternator first. Edited June 23, 2014 by whyverne14 Quote Link to comment Share on other sites More sharing options...
fred heath Posted June 23, 2014 Share Posted June 23, 2014 I'm leaning towards the alternator. If your isolater is a simple two post solenoid your engine battery should still be charging even if the isolater is bad. Put a voltmeter on the battery posts. With the engine running you should be seeing about 14.5 volts. If not, it's probably the alternator. Quote Link to comment Share on other sites More sharing options...
zero Posted June 23, 2014 Share Posted June 23, 2014 Thanks. Since the battery says it's over 3 years old and I just took it down to nothing, it might be wise to replace it. There was a local mechanic at the campsite who said he would do the alternator today but I didn't want to miss work so I took the chance and barely made it home. And besides I had it in my head that it wasn't the alternator. I just found a post on "open roads" who described the same symptoms and said it was not the alternator, it was the isolater. So I'm thinking if the isolater is that little salt shaker on the firewall there, maybe I should try going around that after I get the new battery. All I need is shore power for this weekend, I got to figure out why that wasn't working. Maybe it tripped a breaker. I'm on that learning curve. Thanks again. And I just found another post on here that said it was the alternator. Well full test on alternator first. The alternator senses battery voltage and responds accordingly IF it's working. So to diagnose - you need to know what battery it is hooked to and I assume it's the front battery. When the alternator is running - voltage should come up to near 14 volts. Test voltage at the battery and at the output terminal on the alternator. If the battery is hooked to the alternator and voltage does not come up when running - it is not working. As to the rest of your system? I have no idea if it's original or has been changed (many have). Later Dolphins used low-draw full-time relays to join your front cranking battery to the rear "house" battery once the engine was running. Just a small tin-can and looks like a Ford starter solenoid/relay. Early ones were not "smart" came on or off with the key switch. Some rigs have used "smart" relays that come "on" and "off" automatically by sensing front battery voltage. A quick guess from what you describe - is that your back battery is dead and your front battery is near dead. Correct? If so - check the output of the alternator AT the post on the alternator. Quote Link to comment Share on other sites More sharing options...
linda s Posted June 24, 2014 Share Posted June 24, 2014 Brake and battery light being on is Toyota's way of telling you the alternator isn't working. That shouldn't have anything to do with your coach except when not connected to 110 power. If the coach battery has died from never getting charged properly then you would be dead in back too. If it's still dead after you plug in then you have other issues. Power cord connects directly to the converter and that converts to 12 volt for your interior lights and water pump and stuff. You probably have power steering and auto tranny. Getting the alternator out is a pain. Guy at campsite would have been unpleasantly surprised. Linda S Quote Link to comment Share on other sites More sharing options...
whyverne14 Posted June 24, 2014 Author Share Posted June 24, 2014 Thanks everybody. I'm going new front battery and alternator today. Then I'll see what happens. Back battery is already brandy new. One problem at a time. I bought a volt meter! Quote Link to comment Share on other sites More sharing options...
Nam Posted June 25, 2014 Share Posted June 25, 2014 One thing I learned from my previous V6 Warrior was the alternator did not go bad all the sudden. It "slowly" died where the amount of current pumping out of the alternator was decreasing. Now when I check alternator's voltage, I check at the alternator terminal, not at the battery since the cables and connectors could go bad. This happened on my sister's Camry Quote Link to comment Share on other sites More sharing options...
Maineah Posted June 25, 2014 Share Posted June 25, 2014 The power will go to the path of least resistance so if the alt was doing a poor job of charging your truck battery it was doing even worse charging the coach battery. Charge and brake light will definitely come on at the same time if the alt. is toes up. Quote Link to comment Share on other sites More sharing options...
whyverne14 Posted June 27, 2014 Author Share Posted June 27, 2014 Updating. New alternator in. Drove it home, about 15 minutes. Went in the back, the coach battery gauge is showing 11.7 and everything works. So the mystery remains, why did everything in the back shut down when the alternator went kerpluey? And why should I care? As long as it's working again. Thanks everybuddy for the input. Quote Link to comment Share on other sites More sharing options...
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