wont start hot

[totg]

I am new to this and need some help. 1991 Toyota Truck won't start when the motor is hot. Hot being up to proper operating temperature. New starter. New battery. Drive truck till every thing worms up. Stop & turn off engine. Will not restart. Starter will not do anything. Just click and all gauges and lights dim and go to zero when holding key in start position. Can not use jumper cables to jump off. Must cool down before starting. Several starters and batteries have been tried. Any thoughts on this? Thanks.

[texas12]

Mine does the same thing but only sometimes. Fought with it for months trying multiple things. Never found the REAL fix.
I did find that if I ran a seperate wire to the starter solenoid, it would crank and start. Now I have a starter switch installed on the lower dash. When it will not start, I leave the key in the ON position and push the button. It applies 12v directly to the starter solenoid, bypassing everything else. Works everytime.
Try just running an extra wire from the solenoid to near the battery. When it does not start, touch the wire to the + battery post and see if it cranks. Careful if you have a manual trans cause it will run you down.

[totg]

I ran a 12V line to the starter and your right it does work everytime. I was hoping I could figure out how to fix it so I could eliminate the 12v direct starter button. Thanks for your help

[texas12]

If you figure it out, please share it with me. I fought it for a long time and never found the REAL thing. I am convinced that it is an electrical issue. Only about 7 volts to the starter solenoid when it is happening. I tried tracing wiring, running extra ground cables and trying to disconnect things to recreate the problem. As of late, I have lost interest and time, due to the solid bandaid with the starter switch.
Good Luck!