Heater shuts off on high
#1
Heater shuts off on high
I did all kinds of searches for heaters shutting off when it is put into the 4th(or high) selection. I have yet to find a thread that has this issue. If anyone out there has had this happen could you please post up what you did to fix it. I have a 2004 Blazer 4.3L 4x4. I have checked the fuses and all are good. Numbers 1-3 work fine but 4 shuts the heater down. There is nothing coming out of the vents at all on the fourth setting. Everything else works on the heater control panel. Thanks in advance.
#3
The fan speed resistor is usually mounted on the heater box with the coils reaching inside the box near the fan motor for cooling. Look for a plug near the fan motor that goes to a flat square with one or two bolts holding it in. Sorry I can't tell you exactly where either as I have not had to replace mine yet.
#5
^ I agree. If high speed doesn't work, and all others do, the relay is most likely the problem. It has 5 terminals and is either in the underhood fuse panel, or close to the blower resistor, usually on the firewall. Wire colors are: Purple, black, 2 orange, (one slightly larger gauge than the other) and bark blue.
#6
Thanks for the info, when I get time tomorrow, I will pop the hood and check voltages over the lines and see which one is bad then test the resistors. Thanks again everyone for the speedy response.
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