Blower motor issue

[rhamer88]

I’ve got a 1984 C10 and over the weekend my heater blower stopped working. I’ve been chasing wires a trying to see what happened and I discovered that the fuse for the blower is grounded. It didn’t pop or anything, but when I hook up my test light to it, as in the alligator clip side to a positive lead and the probe end on the fuse, it’s grounded. Is that correct? Doesn’t seem right.

If not, anyone have any idea why or how that happened and what I can do to fix it? Let me know if any further information is needed. Thanks in advance!

[HO455]

If you have the alligator clip hooked to a 12+ source and the probe end to the fuse and the heater switch is in the fan run position the test light should light as the probe is finding ground through the fan motor.

I'm not familiar with the early 80's C10 heater circuits but I am familiar with the late 80's and early 90's S10 circuits. I can't imagine they are very different.

I would start by disconnecting the blower and with the test lights alligator clip on the battery's negative post put the probe in the rubber connector that was connected to the blower. If things are working correctly you should be able to see differences in the test light as you cycle through the different settings on the blower control. If you get no light and your positive the fuse is good carefully inspect the connector as they can break inside the rubber boot.

If that appears to be good move the probe to the purple wire on the resistor mounted on the heater box and test again.

If still no light move the probe to the tan wire on the resistor. Here you should have the light on with the fan speed in low.

If still no light ad you know the fuse is good then you will need to pull the heater controls. My S10 knowledge probably won't help you as the switches are different switches.

Over the years that I've owned S10's I've had numerous blower switches fail, 2 of connectors at the blower motor fail and one resistor fail. If you inspect the blower control you should be able to visually see if it has overheated and failed.

I hope this helps.

[Axle]

1st place I would look is the blower resistor. Comes out with 2 screws. Normally you just lose a speed but it can fully open as well.
Also look inside the blower resistor connector for melting.

If an AC truck, theres a relay mounted to the evaporator box that feeds power to the blower resistor. But start with the resistor.

[truckin 79]

Do you have AC in your truck or just the heat controls?

[Pontiac1976]

I would check the resistor to check the Plug as none A/C is two wire plug and A/C plug 4 to 5 -6 rust some time there just to rusty bad connection or may strict out spring crack at the pin. on the fire wall passenger side