1983 FJ60 'Charge Light' Troubleshooting (1 Viewer)

[Ian Crawford]

Alright, I'm going to give you all the information I have on this.

But first, can anyone tell me what voltage/amperage triggers the charge light on a 60-Series?

For the basis, this is my 1983 60, and I've run a trouble free 31,000 miles on this setup. I have to 80A 3FE Alternator adapted with the correct plug from @Coolerman.

Again, I daily drive this truck with no issues on this setup. Yesterday however, my family and I drove to West Sixth Brewery's farm about an hour from the house. It was hot, so I cranked up the AC (first time this summer) and we cruised along happily towards the farm. As you do in a 60 series, I had to stop for fuel.

Filled up, no issues. Started back up and we had a charge light on solid. Dang.

I turned the AC off and nothing changed. Same amount of illumination at idle or at speed. At speed however, it does flicker slightly following the Volt gauge. Which still looks OK (I know these are notoriously inaccurate) but I'm showing good voltage. I can turn the headlamps on, no change. Rear heater, wipers, etc. No change.

BUT, if I turn the HVAC Fan on (AC or not) on the first setting the light goes very dim. Volt gauge doesn't change. As I turn the fan on higher and higher the charge light gets brighter.

I didn't have an amp meter on me and based on the volt gauge, we continued onward. We got to our destination with no issue and enjoyed our afternoon.

Leaving, we started up no issue. No slow cranking, everything seemed normal but I still have the light.

We drove back home an house with no issues. Thank goodness!

Once I got the wife home and our girls settled in I went back to the garage and got out my amp meter.

Battery shows 12.2V not running.

Start it and at idle the battery shows 13.4V and I get the same at the alternator post. I took everything apart, cleaned all contacts and reassembled with dielectric grease. Test again, pretty much the same voltage and still have the light.

Start it this morning, light still on, bring my amp meter to work, test in the parking lot and I have 14.4V at the battery and 14.4V at the alternator post.

So, what am I missing here? Does the charge light look for something above 14.4V? I feel like this is pretty decent? I feel the 13.4 might have been a little low but not out of question.

Or do I have an unwelcome gremlin? Did I mention the volts readout is the same with the vent fan on low and the charge light very dimly lit?

Thanks for your time!

 

[OSS]

If I had to make only one guess, I'd say that the alternator voltage regulator or its connections are not playing nice.

If I had to make only one recommendation, I'd say replace the regulator and cross your fingers it might fix the problem.

The problem could easily lie elsewhere, but that's my first guess (that could be wrong)

 

[Ian Crawford]

If I had to make only one guess, I'd say that the alternator voltage regulator or its connections are not playing nice.

If I had to make only one recommendation, I'd say replace the regulator and cross your fingers it might fix the problem.

The problem could easily lie elsewhere, but that's my first guess (that could be wrong)

@OSS I was hoping you'd reply. I appreciate it! The more modern unit is internally regulated but I'd convinced myself I was going to replace it though I hate just throwing parts at things.

I studied the wiring diagram for the light and can't find any correlations. Luckily, NAPA has a unit in stock and the price doesn't break the bank.

 

[Spike Strip]

You might ask NAPA to test the Alt before swapping. FWIW, there's a 'Charge Light Relay' under the passenger kick panel that has been known to cause light issues, should the Alt test good. CLR are long NLA and even used ones are expensive (usually), but it's easy to take the old one apart and spritz with DeOxit.

Charge Lamp Relay - Toyota Engine Control Systems

When used, the charge lamp relay is located on the right cowl side of the vehicle. The following steps are used to check this relay Connect the ohmmeter

www.toyotaguru.us

 

[Seth S]

In general the charge light pulls power off of the battery and grounds through the alternator. When the truck starts and the alternator starts to generate voltage/amps this effectively eliminates the path to ground and the charge light goes out. So usually when the charge light is on its because its still grounding through the alternator because the alternator is not generating amperage. So if you are still charging and the light is on....then there is a short somewhere or a problem in the voltage regulator circuit.

 

[HemiAlex]

I find that a little bit of a higher idle works wonders for these trucks. I set mine to about 900 and it helps charging a ton. I ran a bluetooth battery monitor for a while and it showed the trends clearly. The older alternators don't charge much at 700 rpm, but if you watch it at 900...you'll be easily above 13v in most situations. This helped keep my charge light off.

 

[Seth S]

I find that a little bit of a higher idle works wonders for these trucks. I set mine to about 900 and it helps charging a ton. I ran a bluetooth battery monitor for a while and it showed the trends clearly. The older alternators don't charge much at 700 rpm, but if you watch it at 900...you'll be easily above 13v in most situations. This helped keep my charge light off.

Thats a good point...most alternators are not designed to put out their max amperage at idle.

this is a generic charging curve but it gives a good idea how amperage changes from idle

 

[HemiAlex]

Thats a good point...most alternators are not designed to put out their max amperage at idle.

this is a generic charging curve but it gives a good idea how amperage changes from idle

View attachment 2683372

Yep, it worked for me. I was able to run AC and lights on and keep it at 13v. With only the ignition running, its 14v+. I shoot to have the ac idle up hold the same idle as the hot idle...it keeps it all happy. Plus running the fan a little harder keeps it all cooler. There's no downside to me. I was worried about running it too high into the primary circuit from the idle circuit, but the mileage hasn't changed.

Forget the wipers and turn signals, they mess it all up!

 

[Ian Crawford]

I'm experiencing the light at all RPMs with or without accessories on. With the one exception of the blower fan, with the fan on low, the charge light is very dim and gets brighter with each fan speed.

Voltage output measures steady at all RPMs as well.

To @Spike Strip 's point, I believe I have an extra relay I will swap out, that's an easy one to try if I have it. Alternator test will be the next one.

 

[Spike Strip]

My charge light used to flicker at lower RPM and i swapped out the Alt and VR and still did it. Cleaned the CLR and it stopped

 

[Ian Crawford]

Well, I dug through all my Land Cruiser boxes and found about every relay but the Charge Light Relay..... Either way, I popped the kick panel and pulled the relay, everything looked perfect...

Since I already had it out, I gave it a good visual inspection, cleaned it up, then cleaned the plug and reassembled everything with dielectric grease. I didn't start it last night feeling somewhat defeated that the relay was in such good shape.

Went out this morning, started it up to take my girls to the babysitter and go to work. NO LIGHT! I guess it was something with the charge light relay, maybe the connector had slipped out or who knows but I'm sure glad I did throw $140 at an alternator!

As always, thanks for the help fellas.