loss of ignition power on a 81 4x4

ive got a 81 4x4 hilux (not sure exactly what there called in the states) and about 30 seconds after i start the car it loses ignition power, it even loses the constant feed to the ignition switch, i was wondering if anyone has had a simillar problem or if they know of anywhere i can get a wiring diagram or workshop manual so i can try to work out where the wires go off the ignition and try to find the problem

Can you post a picture of the truck to see if anyone in the states will recognize it? autozone.com has wiring diagrams for a wide variety of vehicles.
Haynes repair manuals usually include wiring diagrams. Check with your parts supplier to see if a repair manual is available for your truck. ebay.com maybe a good source to find a used one if you want to save a couple of dollars. Repair manuals in the states usually run about $20.00 USD. Another good source for older repair manuals is repair garages. Some garages sell their old obsolete repair manuals.

what we call a hilux over here is what you call a pickup truck, i think, its a 2 door wellbody, which came out with the 18r and in later years went on to 20r and 22r ect, all the pics and links under pickups i would call a hilux

See if one these diagrams will help.
http://www.autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/18/99/71/0900823d80189971.jsp