Both the Hebrews and Samaritans (a mixed Jewish race treated inferior, yet also dercendants of Jacob) knew Mt Gerizim was the place that Moses told Aaron to divided the 12 tribes after entering the promised land .. there is NO source saying to build a temple on Mt Gerizim, the temple there was an unfounded Samaritan idea .. however, there was saying to build the temple in Jerusalem, to which is also the place Abram was told to build an altar after his faith being tested in Isaac's sacrifice, resulting in a covanent with God .. and the place of "Jacob's Ladder" .. also the threshing floor overlooking Jerusalem that King David purchased from Aravnah the Jebusite (2 Samuel, 24:18-25) ..
Jhn 4:9 Therefore the Samaritan woman said to Him, "How is it that You, being a Jew, ask me for a drink since I am a Samaritan woman?" (For Jews have no dealings with Samaritans.)
Jhn 4:12 "You are not greater than our father Jacob, are You, who gave us the well, and drank of it himself and his sons and his cattle?"
Jhn 4:20 "Our fathers worshiped in this mountain, and you people say that in Jerusalem is the place where men ought to worship."
the Samaritan woman was saying since Mount Gerizim was older, it was holier, not if Jerusalem was the correct site for the Jewish temple ..
Samaritans and Mount Gerizim
The twin peaks of Mount Gerizim and Mount Ebal stand above the Shomron Valley. They may be twins, but they are not identical twins. Mount Ebal is the taller of the twins. Its barren slopes are strewn with gray rocks. This desolate mountain represents the curses that, G-d forbid, could befall the Bnai Yisroel if they do not keep the mitzvos of the Torah. Mount Gerizim, on the other side, has beautiful tree covered slopes and represents the blessings that would come to the Jewish People for following in the ways of the Torah.
Moshe Rabbaynu commanded the Bnai Yisroel that as soon as they crossed the Yarden (Jordan) River they were to take twelve stones from the river bed and build a Mizbayach on top of Mount Ayval. They were to plaster over the twelve stones and carve into the plaster the words of the Torah in all seventy languages. (Deut. 27:1-26)
Six Tribes of the Bnai Yisroel stood by Mount Gerizim and six Tribes stood by Mount Ayval. The Ahron HaKodesh (Holy Ark) was set between the mountains. The Cohanim gathered around the Ahron and the Levi'im gathered around the Cohanim. Everyone turned towards Mount Gerizim and the Levi'im said in a loud voice "Blessed is the man who does not make a stone or metal idol." Everyone called out "Amain!" The people turned and faced Mount Ayval and the Levi'im said "Cursed is the man who does make a stone or metal idol." Everyone called out "Amain!" So they continued, for eleven brochos and eleven curses. (Sotah 32a) Exactly as Moshe Rabbaynu commanded, Yehoshua did soon after crossing the Yarden River. (Josh 8: 30-35)
Mount Gerizim is closely associated with a sect called the Cussim (Cutheans), also called Shomronim (Samaritans).
Many centuries after the Yehoshua divided up the land among the "sh'fatim," the king of Assyria drove the Ten Tribes that lived in the north into Golus. To make it more difficult for them to ever return, the Assyrian king brought in many goyim from foreign countries to take over the homes and land of the Ten Tribes. Many of the foreigners came from a place called Cus. Because of this, all the foreigners were called Cussim (Cutheans). Since the northern district that they took over was called Shomron, they were also called Shomronim (Samaritans).
Of course, the Cussim worshipped "avodah zorah." However, Malbim explains that whereas all the other nations that worshipped "avodah zora" believed in many gods, they did believe that there was a Supreme Being that ruled over all of them. They thought that if you wanted something you had to pray to one of the lower gods. The Supreme Being, they thought, was too busy to attend to your needs. The Cussim did not believe in a Supreme Being at all. They thought the universe was run by a whole committee of lower gods. Because of this, Hashem did not want the Cussim to live in the holy land of Eretz Yisroel.
It wasn't long after the Cussim took over the homes and land of the Ten Tribes that lions started to invade the cities of Shomron. The Cussim feared the lions and they complained to the king of Assyria, "What kind of place have you brought us to?"
The king took one of the Cohanim from Golus and sent him back to Shomron to teach the Cussim about the true Supreme Being, Hashem. The Cussim said that they wished to convert and become Jewish. They wanted to accept the Supreme Being, Hashem. However, they did not wish to give up their belief the lower gods of their religion. And so they worshipped Hashem- and the other gods too. (Kings II 19: 24-41)
There is a major "machlokes" in Shas if the Cussim are to be treated as "goyim" or if they are to be treated as irreligious Jews. Some say that since they only converted to save themselves from the lions, it was an insincere conversion and they are technically still "goyim." Others say that since they wanted to save their lives, they really did want to convert and are considered Jewish; Jews who worship idols.
In either event, the Cussim were not welcomed into the fold of the Bnai Yisroel and there was great friction between the two groups. Years passed, Assyria was swallowed up by Bavel, and Bavel was swallowed up by Medea, and Medea was swallowed up by Persia. The Bnai Yisroel were still in Golus, but now under the Persian kings. Eventually, a Persian king granted the Jews permission to leave the Golus and return to Eretz Yisroel. Upon their arrival in Eterz Yisroel, The Jews immediately began rebuilding the Bais HaMikdash. The Cussim wanted very much to participate in the building of the Bais HaMikdash. They hoped to eventually gain control over the Holy Temple and make it into a place for "avodah zora." The Bnai Yisroel realized all of this and would not allow the Cussim to participate in the building of the Holy Temple.
The Cussim were upset and told the Persian king that the Jews were not building a Bais HaMikdash, but they were building a fortress to fight the Persians. The king ordered the building of the Bais HaMikdash to stop. That king was Achashvayrosh of Purim fame.
It was because of the Cussim that Achashvayrosh had no love for the Jewish people and were almost annihilated, "chas v'sholom," by Haman. Shortly after the death of Achashvayros, his son Koresh (Cyrus) granted the Jews permission to continue the rebuilding of the Bais HaMikdash.
The Cussim were not welcomed into the Bais HaMikdash and decided to build their own Temple. The site they chose was Mt. Gerizim. They knew that it was the mountain of blessing and they claimed that it was the mountain were the "akaidas Yitzchok" took place. They even claimed that the "Luchos," the two tablets with the Ten Commandments, were buried beneath the mountain.
The Gemorah in Yoma tells us a story about the friction between the Jews and the Cussim in the time of Alexander the Great:
The 25th day of Teves* is a day of celebration. No fasting is permitted. It is called Yom Har Gerizim. On that day the Cussim asked Alexander the Great for permission to take over the Bais HaMikdash so they could destroy it. Alexander granted them permission. Shimon HaTzaddik was informed. He dressed himself in the garments of the Cohain Godol and gathered some Jewish nobles. They walked all through the night to meet Alexander. When Alexander saw Shimon HaTzaddik, the emperor got out of his royal carriage and bowed before Shimon. Alexander was being accompanied by some Cussim and the Cussim were puzzled why the mighty emperor would bow before a Jew. Alexander told them that before every battle he dreamt of a holy man that assured him of victory. That holy man was Shimon HaTzaddik.
Alexander granted Shimon any wish. Shimon asked that the Jews be allowed to do to the Temple of the Cussim on Mt. Gerizim what they had plotted to do to the holy Bais HaMikdash. Permission was granted. The Temple of Mt. Gerizim was destroyed and a great celebration by the Jews commemorated that event for many years afterwards. (Yoma 69a)
*in Tamid 27b and in Megilas Ta'anis the date given is 21st of Teves
Over time, the Cussim tried to rebuild their temple. About 150 years after Alexander, their temple on Mt. Gerizim was again destroyed by the Maccabean kings.
Today, there are a few people left who claim to be descendants of the Cussim. A popular tourist attraction is to visit Mt. Gerizim around Pesach time when the Cussim sacrifice their own version of a "korbon Pesach."
http://www.campsci.com/iguide/har_gerizim_and_har_ayval.htm