1997 Blazer Blower Motor Issue

[Takoda12345]

I have a 97 Chevy Blazer 4wd 4.3. It has 189,000 (2nd motor and trans). I have had some issues with the blower not working or periodically working. Today, the blower completely stopped resulting in no heat. I replaced the Relay and Resistor and still did not work. So I returned the parts thinking the blower motor was bad.

I took 2 wires and ran them from the battery to the plug-in coming from the access panel. Sure enough, the motor turned on and now the heat and blower works. Additionally, the interior climate control switch was replaced last year.

The only idea I can think of is a bad ground or some sort of wiring issues. Any help would be much appreciated.

[Airjer_]

Did you check for power and ground to the blower motor?

[Takoda12345]

Originally Posted by Airjer_

Did you check for power and ground to the blower motor?

I have power and ground to the blower motor. I am starting to think it may be something on the climate control.

[Airjer_]

I don't know how that is possible. This is a power side controlled system. If there is power to the blower motor on the purple wire and the ground on the blower is good than the blower has to work. Did you check for power with the connector plugged in and the heater turned on? If there is increased resistance in the power supply circuit it may not show up unless there is a load (poor contacts, burnt up contacts, corrosion, almost broken wires). It might be worth pulling the control head and checking to see if the connectors are burnt up.

[old_master]

That schematic is for manual HVAC, The climate control schematic is completely different. Alldata or a GM factory shop manual will help with diagnosis, don't waste your time or money with Haynes or Chilton.

[Takoda12345]

Thanks for the advice. I just solved the issue. The ground was bad so I just ran a wire from the plug and grounded it to the firewall. Now the blower works fine. It was a quick fix and appreciated the advice.

Now I have another issue. I changed the thermostat (195) and coolant temp sensor. It was running to about 240 so I returned the parts and replaced them. Again, it is running to about 240-250 and then back down to about 210-220. So I figured air got in and bled the system for about an hour. To no avail, its still running too hot. Ive bled and filled the damn thing a few times. No leaks at all. The radiator is less than a year old. I wonder if I have an air bubble in the heater core. I was told I should get it vacuumed out but who knows. I just tuned it up too. Again, the truck has 180k+ on it and burns some oil but never had it run this hot.

Originally Posted by Airjer_

I don't know how that is possible. This is a power side controlled system. If there is power to the blower motor on the purple wire and the ground on the blower is good than the blower has to work. Did you check for power with the connector plugged in and the heater turned on? If there is increased resistance in the power supply circuit it may not show up unless there is a load (poor contacts, burnt up contacts, corrosion, almost broken wires). It might be worth pulling the control head and checking to see if the connectors are burnt up.