On a friend of mines vehicle, the heat/ blower isnt working well. It will only come on every once in a while (short) but i cant figure out where the short is, where should i start?. also, when it does come on, it blows cold almost all the time. The temperature gauge pretty much stays at the lowest point even after being on for an hour. i dont understand why, and she stays cold all the time, and here lately the heat (when hot or cold) actually blows out, it will blow out a very small amount. anyone know what the problem(s) is/are? thanks in advance guys

 

not sure about the short, but the low temp could be caused by low antifreeze levels.

 

Blowing cold - low coolant, thermostat stuck open or not present, temperature blending diverter door not sealing. Due to your comment about the temperature gauge - low coolant or thermostat problem seem to be leading contenders. Should be able to hear the diverter door 'thunk' when you move the temperature lever back-n-forth.

Not blowing - main components will be the switch, the blower motor resistor module, or the motor itself. Suggest to hook 12V up directly to the motor, then go from there.

Good luck, and keep us posted!

 

Sounds like a bad resistor on the blower motor.This is very similar to what you should be looking for:

If you're more worried about the low blowing it also could be leaves clogging up the works. You'll need to pull your cowl panel and spary everything out completely to rid it of leaves and other debris.

 

I agree with the low coolant or stuck open/missing therm. If the problem just began then it probably has a thermostat and its stuck or the low coolant. I just changed my girlfriends in her blazer because her heat was blowing cool also and it fixed it right up.