Greetings,

I'm chasing an issue with the charging system in an '86 pickup/22R and was hoping for some help.
The alt. puts out 12 volts, but does not put out the needed 14+ volts to charge and run lights, wipers, radio, etc. at the same time.

New remanufactured Denso alt.

There is 12 volts at the 15 amp charge fuse at the kick panel.
I think the issue is with the yellow wire (sensor) that runs to the 7.5 amp fuse in the engine bay.

Engine on tests:
volts tested with 7.5 amp fuse in place- .74 volts on both left and right side of fuse
volts tested without 7.5 amp fuse- on left side of socket (side closer to fender) 5.9 volts, right side socket .39 volts
alt. plug, yellow wire 5.8 volts at all connections in the harness to fuse block


Engine off test:
resistance (200 ohm setting) of charge fuse sockets (7.5 amp)- left side (closest to fender) 22.6, right side 0 resistance

Would these results indicate a short in the yellow wire between the alt. and fuse block?
...or perhaps an issue with the yellow wire in the fuse block?
Is there a way to check if the yellow wire is "talking" to the emissions block at the passenger's kick panel?

All suggestions are welcome!
Cheers

 

The 7.5 amp "Charge" fuse is not critical. The charge fuse is merely part of the fault indication circuit. The Engine fuse is critical. You can remove the Charge fuse and a normal charging system would still work. Yes, Toyota's naming system sucked back in those days.
Here:
https://www.yotatech.com/forums/f116.../#post52401963

 

The post you linked is for a 22RE, is the system the same?

 

If u have built-in regulator, red IG, White S, Yellow L on connector, Thick B alt to batt wire on Stud termjnal. Shud be same as 22RE.
Charge fuse does not enable charging Engine fuse does.