Took my hvac box out and replaced the evaporator and heater core. Now my fan only blows on high. One thing after another goes wrong. Please tell me I won't have to pull it out again.

This looks like the blower motor resistor- easily swapped even without removing the dash and hvac stuff.

I would check the connectors first, maybe you did not plug it in correctly.

Yep. Your blower motor might be a little worn too. Neither one hard to do.

If the resistor is blown that's because the blower motor bearings are shot adding extra load on the resistor.

 

...or did you forget to plug it back in?

I re-soldered the contact in the resistor. I guess the blower motor is going out. Thanks.

3 hours ago, slowpokedodge said:

I re-soldered the contact in the resistor. I guess the blower motor is going out. Thanks.

 

Yeap the motor is failing soon.

On 9/30/2018 at 9:02 PM, Mopar1973Man said:

 

Yeap the motor is failing soon.

 

I cleaned my motor and put in new bearings, from some R/C model IIRC, and the fan lasts some years since then.

 

It usually overloads the resistor if the fan bearing gets hard to turn, increasing the amperage on the motor..