No heater

[4X4HIGH]

Ok, I have an issue that just arose between friday morning and this afternoon. I drove my Blazer to work on friday and i'm pretty sure the heater/defrost was working but tonight I jumped in the Blazer and it is definately not working. I checked the fuse(s) and they're all good, the connector under the hood is still attached to the heater box. My manuals are still buried from my move so no access to those ATM. I'm thinking either the switch itself (none of the settings work), or the relay under the hood that's bolted to the heater box?

 

[livid4dirt]

Don't forget to check the pesky little ground wire on the fan motor housing.

 

[Big Ray]

I have had the relay go bad on 2 of the trucks I've owned.

 

[paratrooper307]

The ground wire was loose on mine. You can hardwire it and bypass the relay in order to test. Those are the most common problems, especially if it was working one day and just quit.

 

[4X4HIGH]

I'll first check the motor itself, then the relay, then the switch (I have replaced the switch several years ago and haven't really driven the truck much since).

Does anyone have a wiring schematic for an 89 Blazer for the heater wiring? I dug out my big Chiltons repair manual and there aren't any wiring schematics in it.

 

[4X4HIGH]

No one has a wiring diagram for an 89 Blazer?

 

[dhcomp]

Scott, I think I have an extra resistor kicking around if you want to test it before you buy one. Maybe the relay too.

I'll be back in town this evening


Hell, my house is almost closer than the parts store. Haha

 

[4X4HIGH]

Scott, I think I have an extra resistor kicking around if you want to test it before you buy one. Maybe the relay too.

I'll be back in town this evening


Hell, my house is almost closer than the parts store. Haha

I'm going to try and test a few things right now. The parts store is right behind my house.

 

[4X4HIGH]

All fixed now. Turns out that the motor 12+ volt eletrical connector wasn't making a connection, I could wiggle the wire around and make it work so I just found a spot where it worked then zip tied the connector. I would have just soldered the connection or whatever but the motor is riveted together and I didn't feel like tearing it apart since I don't drive the rig that often.

 

[Big Ray]