u/Expensive-Snow1617

Been having a problem with my truck where it won’t get up to temp. Thought it was the thermostat so I spent a good chunk of time yesterday replacing that. Went to burp the coolant (heat on high fan on low, watch for bubbles and fill gradually while the engine warms up) but it never got to temp. The fan kicked on almost immediately when I started the truck though. Both hoses going to the coolant reservoir were hot and firm but hose going from the fan to the thermostat was warm and soft. Now I think it’s the temp sensor? Or relay? Not quite sure