Electrical System Voltage Issue

[JKohler]

I am really hoping someone has run into the issue that I am having and can help me figure out what is causing the voltage issue that my truck is having. I have a 87 FJ60 and a few days ago I noticed a noise coming from what sounds like under the passenger side dash. The noise sounds like a steady clicking sound, very similar to a noisy heater motor. At first I only noticed the sound in the morning when the engine was cold. When the choke was out there was no noise but when it would idle down the noise would start again and the charge light on the dash would come one (only at low rpm). Saturday night while driving the truck just turned off. I assumed it was a charging issue so I took out the alternator and had it and the battery tested. Both the alternator and battery tested good. So with that I am at a loss for what could be causing the voltage issue, which is basically draining my battery. I am thinking that there is some electrical relay, circuit breaker, or something like this that has gone bad and is now not keeping the circuit together. When the wires to the alternator are connected the clicking noise is there but when they arent connected the noise goes away but then the battery is dead when I shut the engine off. So there is something tripping the system but I have no idea what.

I hope that someone has run into this and can help me out since I am currently driving with all accessories off to save the battery. It is hard in Seattle with no wipers.

You can send suggestions to this posting or my e-mail jason.kohler@hotmail.com

I will appreciate any suggestions...

Thanks,

Jason
1987 FJ60

 

[REKCUT]

I would try testing the alt while its on the car. I am not sure what would drain a good battery faster than your alt could recharge if both are in proper working order. You still have the clicking issue and you might have to just start pulling fuses to locate the problem but i think you have more than on issue going on. Test the battery off and with the truck on.

 

[JKohler]

I have checked all the fuses and they are all good to go. Do you know if there is some type of circuit or inline fuse that is located on the passenger side under the dash? I am thinking that this could be what is clicking and each time it clicks it is opening and closing the circuit so each time it clicks the circuit is broken and the battery doesnt get the full charge. I researched other questions that are similar to mine and found out that there is something called a fuseable link on the positive battery cable. Do you think this could be part of the problem? Are there other fuses that need to be checked that are not in the fuse box on the drivers side lower dash area?

Thanks for your help!

 

[REKCUT]

The fuseable link is located inline with the positive leed of the battery. Its only a couple of inches form the terminal. There is a small computer located inside of the pannel that runs the carb fan. What you need to check on the fuses is have the truck running and pull them one at a time until you get the clicking to stop. That will help isolate the problem. The fuse may be fine but you are trying to locate what is clicking. Again I cant think of anything there that would stop the charge from reaching the battery. When you put a meter on the battery it should read 12 v and when you have the truck running it should be around 14 v. If this is the case then your truck should not go dead from driving. It may click but it should not be running down the batttery to the point it wont run.

 

[JKohler]

Thanks so much for the details. I will check all those things when I get home tonight and hopfully isolate the issue.

Thanks,

Jason

 

[JKohler]

So on my way home from work yesterday I was watching the volt gague and it all of a sudden jumped up to right above 12 volts and then slowly came back down to a little below 12 volts. When this happened the clicking went away...
When I got home I checked the battery with my voltage meter and it showed 12.25 volts (engine was off). I also checked the wires going to the alternator while the engine was not runiing and they all were at 12.25 volts. I started the engine and checked the battery again and it was showing just a little less voltage 12.21 volts. I also checked the wires going to the alternator and the ones coming off it and one read 12.21 volts another one (thick white wire) was at 9.56 volts. This tells me that maybe the alternator is working, but not working up to par. As soon as the truck was running at almost 12 volts the charge light went out and the clicking sounds went away but if I turn on the lights, wipers, the gague shows about 9.5 or 10 volts.
As far as my knowledge goes is that if the alternator was working properly the battery would read 13.5 or 14 volts when the engine is running. Since it doesnt I am thinking that the alternator just isnt putting out enought. Does any know what the wires on the back of the alternator should read? There is also this little tube with a wire connected to it on the back of the alternator. It looks like a condenser like on a non electronic ignition distributor. Should this be there becuase when I bought a new alternator and returned it the new one didnt have this on it.

OH I also tried pulling the fuses in the fuse box one at a time while the truck was running but since the clicking noise went away now that the volt meter is above 10 volts I couldnt tell which circuit is having the issue.

Any Help, thoughts, or ideas would be awesome.

Thanks,

Jason
1987 FJ60

 

[BillNoy]

I recently went thru the same situation. Replaced the alt. and all was well. The condenser on the back of the old alt should be installed on the new one.

Bill

 

[philos1]

Not quite your problem, but I had a similar fluctuation in voltage readings at the gauge in the dash. Turned out to be a mostly melted connection at the fusible link. I cleaned it up, put in a new fusible link and the problem went away for good.

I agree that it sounds like more than one issue here though.

Check your grounds and all connections you can as well.

 

[kevinmrowland]

The "tube" is just a noise suppressor, you swap it onto new alts.

The screw terminal on the back of the alt should be reading around 14v when the truck is running.
As fusible links go bad, they restrict the flow of electricity, they still pass a continuity test, but if you pull the plug on the battery side and test for voltage you will see a drop in voltage across the link.

It sounds like what you have is a set of worn brushes and possibly a faulty voltage regulator as well.
Both these parts are available, OE or aftermarket, I have a reference thread floating around with part numbers.

 

[JKohler]

Thank you all so much for all the input on this issue. I think I may have made it out to be more that it had to be but since the guys at Kragen tested my old alternator and said that it was good I was at a loss as to what else it could be. Yesterday I verified everything that had been suggested on this string and I had made no progress or hadnt found anything that would shed light. I decided to just go and get a new alternator and change it out. So last night I put in the new alternator, noise supressor, and cleaned all the connections. I fired it up and what do you know; the gague read roughly 14 Volts! I guess I should have just gone with my gut feeling but at least I learned a lot about the charging system and my Cruiser.

Thanks again for all your suggestion it really helped me out...

Now I just need to find someone who will swap pulleys for me

Jason
87 FJ60