Hi. I'm new to this forum. I have a 1990 Toyo 4Runner which is experiencing some electrical difficulties. It seems that there is a fault in my charging system (I isolated it by pulling fuses - ghetto I know), and I cant seem to find where it's shorting. All the wires seem to be intact, and all the fuses are in good condition. The symptoms are all the trouble lights seem to come on except for the engine check light (so.. ebrake, a/t oil temp, battery charge), and there is more drain on the system than the alterator can handle (causing the truck to stall). I've replaced the alterator twice, and have gone through about 5 batteries this year (the first 4 were related to a faulty alternator).

Many thanks, Mike.

 

Welcome to YT Mike.

Buy yourself a digital multimeter (they are cheap, some less than $10) and learn how to use it.

There have been some people that have had their trucks catch fire because of a wire shorting so don't let it go, or at least keep the insurance paid up.

 

Welcome Mike.

No check engine light means either bulb blown or the ECM is not powering up. The ECM is behind the kickpanel on the passenger at the floorboard and under the dash. If you've not looked in there, yet, it would be a good place to start. Pull the connector from the ECM with the battery unhooked. Look for any corrosion or burned terminals. Then, pull the covers off both sides carefully and look for the same. If all looks good, then starting looking for corrosion at the fuse box under the hood on the pass. fender well.

While it may not be the source of your overall problem, it might be part of it. You will need to check all the major grounds....even though they are connected they may not be getting good contact. Like Mt. Goat said, getting an ohm meter will help. That way you can test the resistance/continuity for wiring and fuses where nothing is visually apparent. Saves lots of time and effort from pulling a bunch of parts and whatnot off.

I'm also wondering....as simple or silly as it may be...if you have the alternator hooked up correctly?

Post back on what you find with these suggestions.

 

So I checked all the major grounds, and I checked the ECM. All of the grounds have continuity, and the ECM does not appeare to have any scorching or fried wires. And yes, the alterator is installed correctly. It's wierd... When I pull the fuse marked 'charge' or the marked 'engine' everything starts to work again. However, as soon as I plug either one back in, I get this huge load on the system that almost sucks the battery dry.

Any ideas? I'm at a loss.

 

Update!