Charge Lamp - Intermittently Lit upon Starting

Joined
Nov 6, 2016
Messages
5
Location
Los Angeles
Sometimes the dashboard Charge Lamp on my '84 FJ60 does not light when I turn on the ignition. Without a lit Charge Lamp, the cruiser wont run properly, and I fry my alternator. We've changed the Charge Lamp relay, alternator, checked all voltage, checked grounds, corrected shorts, checked the wire-harness to ignition switch, etc. ( Jim Dickey and I have spent hours and hours and hours on this). The truck runs perfectly when the Charge Lamp is lit at start. Perfectly.

When the truck hasn't run for a while, the Charge Lamp lights at start almost every time and the truck runs without a hitch. But after about an hour of driving, the truck stalls (stops charging properly). When I try to re-start the engine, the Charge Lamp will not light, and the truck will stall if I start the engine without a lit Charge Lamp.

I've spent many an hour in a parking lot switching the ignition on and off until the Charge Lamp lights, at which point the truck runs perfectly and I can drive away, until it stalls again.

We've racked our brains on this. Has anyone out there experienced a similar problem and found a fix? MP
 
Joined
Mar 31, 2014
Messages
4,468
Location
Gone
I don't know what the problem is, but I can tell you this for certainty: the engine doesn't require the alternator to run.

It requires power from the battery (maybe 6 amp) and can run off a good battery for many hours without any alternator at all.

The usual cause of instantly frying an alternator is from disconnecting it from the battery while it's running.

The charge light on the dash is incorporated into the ignition system. That's where I would be snooping around. It seems like there is an intermittent circuit break somewhere. Just guessing.

Carefully examine the Fusible Links too. Maybe a bad connection in there.
 
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Spike Strip

By The Book.
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Joined
Nov 22, 2005
Messages
14,445
Location
Los Angeles, SFV
 
 
I did two things at once which corrected a similar thing with an intermittent charge lamp: I swapped out all the battery and ground cables for the 00 gauge kit that Urban Land Cruisers sells (LINK). At the same time I made sure ALL grounds were clean and metal to metal then painted over them. At the same time I removed and took apart the Charge Lamp Relay and cleaned it thoroughly with Gold DeoxIT. After that, the lamp functioned normally, but my AMP indicator still reads low when the lights are turned on, though the ALT output is fine.

FWIW, charge lamp relay is NLA from Toyota and no aftermarket available.

:meh:
 
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