Hvac relay?

[Brock]

Problem fixed, it was the resistor.

[gatow900]

(08-07-2017 )Rawze Wrote:  

(08-07-2017 )Brock Wrote:  Oh ya, I'm far past that point. I've realized now there is no relay, direct power right to the resistor and the resistor controls the rest. So, off to town to get a new resistor.

Mine in the back bunk went bad. I wired a 30-amp relay up to it and a switch to control the relay that comes on/off with the ignition. I am likely going to make it 2-speed, so I need to limit the current when it is on low...

To limit current, I tested the blower in the bunk with a tail light from my car wired in series instead of the bad controller. It was blowing about 20-25% or so. A truck headlight bulb would likely have the right resistance to make it roughly about 50%. I am thinking of using the headlight bulb ( mounted into the air stream to keep it cool ) instead of a bulky resistor in series with the motor to limit current is the way to go. That way if it goes bad, I can replace it on the cheap and every truck stop would have one.


A am testing all this because my front one is next. It is getting flaky and cutting in-out on the higher settings. I will need to make a simplified 2-speed control for that one for sure.


It s a truck, not a luxury car. I don't need a computer and 10 settings for the blower LOL.

i think something like this is very low tech

[1096]

"Sounds good but the blower motor is about 15 amps current. Find me a 20-amp rheostat that is not the size of a stack of dinner plates lol. Those things are HUGE!"

I found it! It's called a Dimmer Switch. From your local hardware store, maybe $15. Let me know if you blow it up. Could save me some money.