My 88's temp sensor(ECM) is on the drivers side of the water outlet top rad hose. The temp sender switch (Gauge) is on one of the corners of the cyl head. This one might be hidden by the a/c bracket or rear firewall. Wire colors are as Mike described.

 

well after amonth, i finally found the old part and got the new one in. I am waiting for a new brake line, so i cant test it to see if my overheating problem is fixed. if not, a new fan motor is next. thanks for th ehelp guys!