Hi, I've replaced both temp sensor and sending unit; however, my temp gauge still isn't working...im replacing my radiator, it appears the previous owner didn't exactly take care of the coolant system. the temp gauge didn't work when i bought it. what could be the problem?

 

To test the gauge, bridge the contacts in the connector for that sensor. Gauge should read full hot. To test the sensor, remove it from the block, reconnect it’s electrical connector and heat the sensor with a bic type lighter. Have a freind tell you if the gauge registers any heat.