Auto Parts: Temperature gauge, toyota tercel, temperature gauge

Question
I have a 1998 Toyota Tercel. When I turn on the ignition the needle on the temperature gauge immediately goes past the maximum and will not go down. It falls back below zero when the ignition is off. what could be the problem

Answer
    This one's easy.  There is a sender screwed into the water jacket, usually in the cylinder head, that sends the signal to the gauge.  One of two things has happened: either the sender has failed in the closed (shorted) mode, or the wire that attaches to the sender has come loose from the switch and grounded itself against the engine.  Another less likely thing would be that the wire has been pinched by something, cutting the insulation and grounding the gauge.  Has anyone been mucking around under the hood?  Even someone doing something as innocuous as adding or checking the oil could accidentally knock the wire loose.  If you don't see any loose wires, you might want to buy a new sender if they are not too expensive (Pep Boys or similar should have that one in stock).  Find the old one and unplug the wire and plug it into the new one.  Hold the new one against the engine to ground it, and have someone turn on the key and see what the needle does.  If the needle doesn't swing over like it's been doing, then go ahead and replace the sender.  If it does, then there is something pinching the wire and you should trace the wire backwards from the sender to find the fault.  It is remotely possible that the fault is in the printed-circuit dash in which the gauge mounts, but if it is, you will want to just do without that gauge, the repair would be very difficult and expensive.