Level 4 on the speed control for heat/ac doesn't work. Levels 1 thru 3 work fine. Before it went out I heard a whining noise on level 4, now there is nothing. We replaced the resistor and that didn't work.

What do you suggest is needed, the blower motor or a switch? I already have the motor but someone told me it was the switch, so what should I do?

I've searched many places and there seems to be mixed results.

Or should I just replace both?

Thanks

 

well if you already have a motor, could try throwing it in, but I doubt that's the issue, and if the resistor didn't fix that it sounds like the switch itself....

 

Probably switch, pull it out and look at the connector and look for melting or charred areas, if anything looks like its been hot you will need to replaced that pigtail/plug to the switch. Position 4 is full power so it send a lot of amperage through the switch, had the one in my astro melt off while i was driving, i smelled hot plastic and saw a little trail of smoke coming out of it and tried to turn it off and the **** came off in my hand with a big string of hot melted plastic drooping off it, ripped the dash apart while i was rolling down the interstate and unplugged it...fun times!

 

Really ironic I had the same thing happen to me on my 1998 Blazer just yesterday. Level 4 burned up but 1-3 still work. Let me know if ya find anything out. I would guess that they are both the same issue. Someone posted on my post that it may be the relay behind the glove box. I am content as long as 1-3 still work but I do not want the whole fan to die.

 

Haven't changed it yet, we installed a new water pump instead. When on setting 3, it seems to blow hard and then very light and back to hard, does this have anything to do with the switch I'm about to replace?

 

Speeds 1, 2, & 3 are routed through the blower resistor. BWD HVAC Blower Motor Resistor RU1027: Get the best Blower Motor Resistor at Advance Auto Parts If any of them fail, the resistor is the most likely cause. Speed 4 bypasses the resistor and sends full battery voltage to the blower through a relay. If 4 is the only speed not working, the high blower relay is most likely the cause. The relay is located in the center of the firewall. There are 5 wires going to it, and it is approx 1" cube.

 

The pig tail plug your talking about. Is that the small square plastic piece in the center of the fan switch that holds the contacts close? If so, I had one fail, smoke when I turn the fan on. Bought another (used) one and that didn't even last a day. Can't find another one anywhere. Any ideas where to get another one?