Intermitant Charging

[phins]

I recently left my yotahome without turning it on for a week and came back to find the auxiliary battery nearly completely drained; the lights would barely glow (This is troubling enough on its own, but there is more). To find something in the dark I turned on the engine. This made the lights immediately bright. After about thirty seconds they when back to dim then flashed back and forth between the two states of dim (battery) and bright (alternator) for the rest of the time the engine was running. This was accompanied by a subtle but noticeable change in the idle the dim state being slightly rougher/heavy load. I thought this might be due to a loose wire establishing an intermittent short, but rocking the home back and forth had no correlation to the changes in the states of the lights.

It should be noted, although I'm not sure the two are related, that I have some dash electrical problems in the spirit of full disclosure. The engine light comes on from time to time, the brake light is constantly on, the cruise control works sporadically, and the charge light blinks faintly sometimes at start up.

All of this and the considerable amount of time I have spent looking for a short in the camper section are conspiring to make me figure I may be in for a visit to a professional. I know it can be something like writing a blank check to take a car in to a mechanic and say 'I think I might have a short'. Any ideas of what I can do to help isolate the problem to keep mechanic cost down? I am familiar with electrical engineering and I have a voltmeter, albeit a cheap one, so don't hold back.

Thanks so much for reading and any suggestions.

[Alvin]

You need an exorcism. I don't think that an 86 has a vehicle computer does it?

You may go at the problem by disconnecting systems as possible in an attempt to find a known good starting point.

[phins]

Thanks for reminding me to add year make model etc. 1986 Dolphin 22R EFI. Yes it does have a computer (maybe 2) at least one I'm aware of.

As far as one system at a time I have gone through the home wiring from the battery compartment. I took the battery out and used the ohm meter to test the resistance between the leads. I got what seemed to me a pretty low resistance, I think it was on the order of 10kOhms, although I'm not sure what to expect and I'd have to recheck to be sure of that figure. Also I have some lack of faith in my ohm meter, even so I traced it back to the AC/DC converter for the shoreline which was also the routing area for the lights and tank meter. This is the point of a major divergence of wiring, so I haven't had the time/ambition to get past there.

As for the exorcism, maybe I'll park the Dolphin in front of a church to see if that helps.

Thanks for the response. I'm going to try disconnecting the auxiliary side of the battery isolator tomorrow while it is running to see if the idle shifts and voltage outputs at the aux pin continue to occur. This might help me to nail the problem down to Toyota or Dolphin issue.

[Maineah]

Get a volt meter on the battery and see what it says. Your on the right track disconnecting the coach battery. The regulator is inside of your alternator and there is no fixing the regulator it would not surprise if the regulator was more then a remaned alternator. See what happens with the voltage and disconnecting the rear battery first.

[phins]

The regulator is inside of your alternator and there is no fixing the regulator it would not surprise if the regulator was more then a remaned alternator. See what happens with the voltage and disconnecting the rear battery first.

Yes the regulator is bad. I am seeing about 16.6 V at the battery isolator and the charge and brake lights flicker in unison which is apparently the result of two much voltage to the charge light overpowering a small diode that has been installed between the two lights. This is an indication of failed regulator. I bought my last alternator from NAPA and they are going to honor the warranty but before I install the new alternator I want to make sure that I don't have the same troubles.

I read on a 22R site that if you put in a reman-ed alternator, jump the car and then let it charge the dead battery it can be overdraw and ruin the voltage regulator. I figure the same issue can occur when there is a short in the camper section. I put my DVM between the battery isolator and the aux battery, with the aux battery disconnected, and I found a current of almost exactly 0.5A.

My question is, do you think that the over voltage from the alternator without a regulator is causing the this 'short' through a designed in current dump? I am worried that if I put in the new alternator it will blow the regulator again as soon as I hook up the camper electrical due to this short, if it is a short.

Thanks for the consideration.

[Maineah]

The charge light and the brake light will come on at the same time if you have a alternator issue. Also there is a relay that turns the lights on . Some thing else you might check is the 7.5 amp charge fuse. Your diode probably is to keep the brake light from back feeding the charge light. If your coach battery system has a short you'll soon end up with a blown fuse for some thing in the coach or a dead battery. It might be a good ideal to yard the coach battery out an have it checked. Did you check the voltage at the truck battery with the coach battery disconnected? An open connection will drive the alternator voltage up never ever disconnect a battery to check for alternator output.

[5Toyota]

I recently left my yotahome without turning it on for a week and came back to find the auxiliary battery nearly completely drained; the lights would barely glow (This is troubling enough on its own, but there is more). To find something in the dark I turned on the engine. This made the lights immediately bright. After about thirty seconds they when back to dim then flashed back and forth between the two states of dim (battery) and bright (alternator) for the rest of the time the engine was running. This was accompanied by a subtle but noticeable change in the idle the dim state being slightly rougher/heavy load. I thought this might be due to a loose wire establishing an intermittent short, but rocking the home back and forth had no correlation to the changes in the states of the lights.

It should be noted, although I'm not sure the two are related, that I have some dash electrical problems in the spirit of full disclosure. The engine light comes on from time to time, the brake light is constantly on, the cruise control works sporadically, and the charge light blinks faintly sometimes at start up.

All of this and the considerable amount of time I have spent looking for a short in the camper section are conspiring to make me figure I may be in for a visit to a professional. I know it can be something like writing a blank check to take a car in to a mechanic and say 'I think I might have a short'. Any ideas of what I can do to help isolate the problem to keep mechanic cost down? I am familiar with electrical engineering and I have a voltmeter, albeit a cheap one, so don't hold back.

Thanks so much for reading and any suggestions.

5toytaihave owned5toyots inc 1978 moter home this is werd but comon beleve it or not thebrake light will comne on with or with the charge light when the alternater is not charging mabe interment had thison1977toytacorona wagen

[5Toyota]

5toytaihave owned5toyots inc 1978 moter home this is werd but comon beleve it or not thebrake light will comne on with or with the charge light when the alternater is not charging mabe interment had thison1977toytacorona wagen

this drove me nuts i had friend toyota dealer mecnic told in my case alt brushs bad bad diods willallow batt too drawn out