Hey all, newbie here. I drive a 93' Blazer that is still running strong after 200k on it. The last couple weeks my heater is only working about 75% of the time, it produces heat fine, but the blower will just kick off every now and then. I have installed a new switch and heater relay but still having issues. And of corse this has to happen the time of the year when the temp has not even hit double digits in the week. Anyone have any other ideas what this might be? Thanks

 

Sounds to me like you are starting to have issues with the blower motor. I would start by checking the electrical connection to the blower motor itself and work back from there to the climate controls in the dash. Check all of the connections by disconnecting them and inspecting the pins and the recepticles for signs of corrosion. Before putting them back together, get some dielectric grease and put dabs of it in the connector. This will protect the pins from corrosion. If you find corrosion, it needs to be cleaned off or the connector needs to be replaced. I have found that, although difficult, the connectors can be disassembled and the recepticles can be cleaned. If you decide to do this, be patient and very careful. At the worst, you'll end up ruining the connector and have to put a new one on anyhow.

If you find that a connector is loose/corroded and it cannot be repaired, I would recommend that you solder and then shrink wrap the replacement connector.

Now if you find that all of the electrical connections look good, then I'd have to start leaning towards a faulty blower motor. If you can hit the blower motor (when it's not working), and it starts to work, that leads me to believe that the contacts inside the motor have gotten worn. If the motor itself is going bad, then it simply needs to be replaced. I'm not sure if the '93s have the same blower motor location as the '96+, but if it does, it doesn't look like all that tough of a job.

Good Luck