knac1234

Hi all,

I started a new thread as this initially started with looking for what I thought was a parasitic draw on my 86 Toyota Pickup, carb/base model.

Background: About a month ago, I went out after a few days of not using the truck and the battery was dead. I charged the battery, and all was fine (I tested for any parasitic draw, but it was at most 7 mA or so). Until a couple of days ago, all was fine for the month, using the truck 3-4 days a week. Then, once again the battery was dead.

After recharging the battery and starting the truck, by chance I noticed that the white wire from the 80A fuse to the positive battery terminal was getting pretty warm. So, until today, I chose not to use it!

Today, this is what I have found and done:

-The white wire (which I have learned on here is a fusible link wire) gets fairly hot. Following the wire with my finger to the backside of that 80A fuse......it is very hot.

-I started by cleaning up the ground from the battery terminal to the fender. I also installed a new ground wire from the battery terminal to the fender as the old one looked original and pretty rough. Note that just under 2 years ago I also installed a new positive battery cable to the starter and an additional ground cable from the battery terminal to the engine block.

-After doing that, nothing changed. No other wires in the main fuse box or the fuse box in the drivers side kick panel felt warm to the touch (or around the steering column).

-I used the Haynes manual to identify other white wires, most of which seemed to lead to the alternator or ignition switch. The single stud terminal with the white wire on the alternator was very hot. And then, I noticed the actual casing of the alternator was very hot. And this is all after the truck running for 2 minutes or so from cold!!!

-The alternator registered a normal charging voltage (13.8-14.1 at idle, and ever so slightly higher...low 14s.....when I increased the rpms).

Any ideas?! Even though the alternator appears to be charging fine, perhaps it is shot? Could it tie into what I thought previously was parasitic draw??? Maybe charging on occasion (although no charge light ever comes on, except when on the ignition position prior to starting the truck).

Thanks for your thoughts....
Julian

prcnctoyo

A few years ago I had a parasitic drain. It was the alternator. I don't remember specifics of diagnosing but I do remember the charge light never came on.

knac1234

Thanks for the quick reply!

I decided I would try one other idea. I installed the battery from one of my other cars, and started the truck up. 2 minutes passed.....no hot white wire at the fuse box (or under it when feeling with my finger)......the stud on the alternator was good and the casing was not hot. I let the truck idle for 15 minutes, and the same.....no heat anywhere! I tested the alternator output, and it now registered higher....a fairly steady 14.5 volts.

After thinking about it, I did notice that my battery charger seemed rather hot after charging the battery back up, but did not think too much about it at the time.

I think perhaps the battery itself then is the issue. It is too coincidental that, when swapping it, all of the extreme hot issues went away; the charging of it on the battery charger produced a hot charger; and the alternator now functions better in terms of charging output than before. Not to mention that perhaps a weak battery explained what I thought was initially parasitic drain. Found the date code on the bottom of the battery too.....May 2018.

Thoughts.....could a bad battery cause this as, at this point, I plan on buying a new one tomorrow!

Julian

Discombobulated

Well, anything is possible with bad cells, personally I have never had a bad batt do anything odd besides die BUT if it’s just a standard battery and nothing special 6 years is about the lifespan give or take. All you can do is give it a go, I would imagine the batt is due anyway.

Report back

knac1234

I changed it yesterday, and ran it without any heating issues and with good, consistent charge coming from the alternator.

If anything changes I will let you know.....all I can say is it started this morning at 6a fine and likewise when I left work at 6p!!
Julian