Hello,

The check brakes light (the one that lights when the parking brake is on, or when the fluid is low) and battery light have started coming on occasionally when I first start the truck. They stay on for a little while into my drive and then turn off. Brake reservoir is full, and it's cranking over strong even with the headlights on.

Anyone seen this before? 1990 4Runner 4x4 3vze 5sp.

 

Alternator or diode is going out. Also, could just be the brushes. You can replace them for under $10 yourself.

 

No kidding? Are the diodes built into the alternator, or is it a separate part like on old MOPAR vehicles?

I take it that in any case, I'll have to probably pull the distributor (to get to the alternator) and the alternator itself?

 

Done and done. Best to remove the entire intake tube from the airbox to the manifold. FSM says nothing of the sort, but I did the whole job in about 35 minutes. Bought a cheap O'Reilly's aftermarket job, but for $175 including the core, it was a deal.

Also tested the battery, which came back good.

I'm keeping the core for a rebuild.

We'll see if that does it.

 

Reference for others.

Link>>> http://www.ae86drivingclub.com.au/fo...-22RE-4AGE-etc

 

Wow. Great write-up on the alternator brush replacement.

It'll be interesting to see what mine look like when I get it apart. The light only came on in the morning since it's been getting cooler at night (40's °F). It would go off once it warmed up.

I'm betting the cold increased the brush gap a little too much. That, or as TNRabbit suggested, a dying diode.

 

I dont know about the diode. One problem I didnt understand when seeing the right up was getting the brushes out. You have to desolder the two contacts out of the brown block and that will free them up.

Most likely the new brushes will be twice the length as your old ones, but you probably have around 150k miles on your alternator so they lasted quite awhile.

 

249,486 miles on the original one.

 

^^^^ Danggg, You got your moneys worth out of that one.lol

 

Out here in AZ, batteries are toast every 18-24 months, but alternators can run forever. This is part of the reason I didn't mind using a cheap reman temporarily while I rebuild the old N/D part. Short of an outright manufacturing problem, I'll get 5 years out of the cheap one.