Overheating

Good morning,

From your description, it sounds like the heater core may be clogged with debris. I would remove the heater hoses and use a garden hose to flush it of all debris. I would do it several times back and forth until you get a good even flow.

https://www.2carpros.com/articles/car-heater-not-working

https://www.2carpros.com/articles/replace-heater-core

If that does not take care of it, the heater core will have to be replaced.

As far as the overheating itself, I attached a wiring diagram for the fans. Without the fans working especially at idle, the car will overheat as there will not be enough air flow through the radiator.

https://www.2carpros.com/articles/engine-overheating-or-running-hot

https://www.2carpros.com/articles/how-an-electric-cooling-fan-works

Do you have a voltmeter or test light to do some checks?

https://www.2carpros.com/articles/how-to-check-wiring

Roy