I have owned many trucks and 4Runners over the years. Renew the clutches and brakes and drive em another 100,000 miles. I have an 89 4Runner. No B+ voltage at diagnostic port. I have replaced all relays and followed your expert advise, THANK YOU! But, still will not start or run. Can I run a toggle switch from ignition voltage to the FP at the diagnostic port? The switch would only be hot when the key is on. I need my rig and will keep searching but right now I am need to use my rig.

Thank you,

Loren

 

Did you check the continuity of the fusible link that goes from the battery + (positive terminal) to the relay box in the engine compartment?
It originally comes from the factory as a white, fairly thickly insulated wire, that runs directly from the battery to the bottom of the 80 Amp relay in the relay box.
To be able to check continuity, you MUST remove the battery negative terminal. If not, you could get hurt, or something might be severely damaged in the vehicles electrical system.
Then, you need to remove the screws holding the relay box in. Flip it over, and you can access the bottom of the 80A relay, where the fusible link goes. Just set the multimeter on it's lowest ohms setting, and put a lead at either end of the white wire from the battery. Below .5 ohms, the FL is OK. Much over that, it may be bad, or going bad. Replace it. It's available on line. I think I have a link to where you can get it saved off someplace. I'll try and find it, or you can google it.

I hope this is some small help...
BTW: I live in Oregon too. Near Klamath Falls
Pat☺