KettleHouse

1984 Toyota truck, 22r, 2 wheel drive

Out of nowhere my "Charge" light on the dash came on and after driving for about 30 minutes and then trying to start again it was not getting full power and was difficult to start. My battery connections were corroded pretty bad, so I cleaned them all off and still had the same problem. When the truck is running and I move a battery cable to disconnect it, the motor instantly stops running. I checked all the fuses and they were all good. Before this happened the Parking brake light has been on for about 3+ months. When I rev the engine up both lights turn off. What would reving the engine up have to do with turning both the Charge light and the Parking break light off?

Can I check any other things before I go and replace the alternator?

creswellhick

sounds like it to me in my opinon my dads 80 did the same thing we changed it and it stopped

xxxtreme22r

Charge and brake lights come on at the same time when the charging system fails. Revving the engine lets the alternator turn faster which allows it to put out more voltage. In short your alternator is most likely bad. This is assuming the first gen trucks had an internal voltage regulator not an external one. But even then, since revving the engine improves charging, it's most likely the alternator.

KettleHouse

I replaced my alternator and I still have the same problem.

It was at 17 volts when running, here is a guy who had the same problem, but he replaced his alternator and the problem was solved: https://www.yotatech.com/forums/f116...rnator-196151/

What would cause it to be so high, I heard 14v is average, but 17 is really high and will most likely kill my battery

wyoming9

iTrader: (1)

Did you have a full charge on the battery when you installed the new alternator??

Did you have the old Alternator checked??

It is possible you got a bad alternator it happens all to often these days.

Where did you measure the 17 volts ??

81tonka

do you have an external regulator?

myyota

84 toyota trucks have an external voltage regulator, and they can go bad like an alternator causing the battery not to charge.
It is posible to upgrade to an 85 and up alternator with an internal voltage regulator. Do a search and you will find the thread here that tells you how to do the wiring.

KettleHouse

I have installed a new alternator (I turned in my old one for a discount and the guy at the store tried to check it, but I don't think he knew how to use the machine, he seemed uncertain and said something like "it's charging but no voltage", so I can't really count on that test) and a new voltage regulator and my brake light and charge light are still on. The battery keeps dying, either because it's not getting charged or I ended up frying it when it was running at 17+ volts. I have gone through all the grounds and wire brushed them and inspected a lot of the wiring and nothing seems exposed.

After I put the voltage regulator on it, it went from 17+ volts to averaging about 9 volts when idling, but I've heard it should be at about 14 volts. I was measuring it by putting a multimeter on the battery connections, on both the positive and negative, is there a better way to measure it?

Is it possible for the brake light and charge light to still be on because of a bad battery, or does that mean something else?

The truck runs strong, but the dash lights go dim and bright when driving.

myyota

Thats the way to test it. One reason why its a good idea to upgrade to an 85 and newer alternator is because the 84 externally regulated alternator is only 40 amps, the 85 and up alternators are 60 amps.

peow130

Its possible your main wires have gotten broken, stripped, or chewed through.

KettleHouse

I bought a new battery, and the lights are still on and when I remove the battery cables and measure it from there it is at 7 volts while running

When I am driving the brake light and charge lights will go dim and bright when I have my blinker on.

I tried to go through as much of the wiring as possible, but was unable to find anything.

mwc0404

try your multi-meter directly at the alternator pos and neg, if you get better results it could be a bad connection or wire between the alternator and battery. If your getting a high output at the alternator then you have a bad alternator or regulator.

Keep us posted

KettleHouse

I took my alternator to the auto store and swapped it for a different refurbished one. Installed it and have the exact same problems. Brake/Charge lights are still on, it shows 12.5 volts when testing on the battery running and 7 volts when I take the cables off.

Not sure where to go from here

mwc0404

Did you test directly at the altenator? If your only getting 7 at the battery cables then the alt is bad or you have an issue in the wiring between the alt and battery

wyoming9

iTrader: (1)

If you keep putting alternators on with out charging your battery you will have problems.

Check the wire coming off the B terminal of the battery they tend to cook over the years and get brittle.

Does your battery take a charge??

KettleHouse

I tried on the last alt and it wasn't giving me a good reading, it said 2.5 or so (even though it said 7 at the battery connections), but I couldn't get in there to get a good reading. I will try again on this one later (I broke the tension belt bolt, so after I get a new bolt I will try


It's a brand new battery. I'll check the wires again, but I have already gone through a lot of the wiring. The ground wire coming right off the battery seems good, I wire brushed where it connects to the frame

Are there any inline fuses that I should be looking for, other than the ones in the fuse box?

--

KettleHouse

Making progress!

In the fuse box in the engine compartment, I unplugged the bottom left set of wires and when I started my truck, both lights (charge/brake) were off, and the car was running at 13.5-14 volts.

Everything seemed to be working great, other than my headlights, they did not turn on. So there is some kind of short or ground wire within the headlight wiring that seems to be causing all the, and when I unplug that set of wires, its all good.

I am unable to find a diagram of what that set of wires is, so I don't know what it's called. Hopefully I can backtrace it to where the problem might be.

GuitarMike

Exactly, Kettle...get tracing! A short, even one that isn't a 100% short but has some low resistance, will eat power and drop your voltage. If you can find the ends of the wires, read the resistance to a known, good ground. Should be low, but not ZERO.
Probably easiest to just find the wires and trace them back from headlights to fuse box/switch. Hopefully it's not in the control column at all....

KettleHouse

I went through all the headlight wiring and it was all good, but the headlamp connectors were bad, I replaced those, but still no change.

Now it seems to be running high at about 16.5 volts. I already put 2 new voltage regulators in. What are some reasons it would be running at high voltage with a good regulator?

KettleHouse

So, after 2 new alternators and 2 new voltage regulators I am still overcharging at about 16.5 volts.

Everywhere I search online talks about the alternator or the regulator having problems.

What are some other, more uncommon reasons for overcharging?