WHen it isn't working, you need to check to see if there is power to the blower motor. IF there is power, the motor is the issue. If there is no power, then you need to check the relay.

So I should check the motor independently? Remove it and check it? And where would the relay be located?

Thanks for your quick response! It's cold in Minnesota today. 14 degrees below zero this morning.

Wow, I thought it was cold here in PA. You can keep it, but I know tomorrows high is going to be 4 degrees here. Hell that is a heat wave for you.

As far as the motor, just check to see if it is getting power. You don't have to remove it. As far as the relays, they are under the hood in the power distribution box.

Ok. I'll check them both out tonight if I can get my garage heater to work. I'll let you know what I find.

Thanks again.

Good luck and keep warm

Ok. It is warmer today in Minneapolis. Here is what I did so far. I took the resistor off and checked the wiring harness. That seems to be in good condition. Next I put jumper wires straight to the blower motor, and connected that to a 9V battery. The blower works.

When the ignition is on, I get power on the middle/red wire on the harness, regardless of the setting for the fan speed. I am not great with the wiring diagrams in the Chilton's manual, but shouldn't I be getting power on different leads for different fan speeds?

I have a digital voltmeter, so I can do some checking on the resistor, but I'm not sure how to go about doing that. The resistor is over $100, so I want to be sure I have a bad one before I buy a new one.

I'm not sure If I explained it well enough in my first post, but once the fan comes on, all the speeds work. The problem is that the blower motor sometimes does not come on, regardless of what I do.

Thanks!

looks like one of my pics didn't work.

Update - I took the part out and went to the Chevrolet dealer to get a new one. Once I got there, the old parts guy spent about 10 minutes on the computer, kept asking me what kind of vehicle I had, and then finally told me that the part I had taken out of the truck isn't for my truck! It looks identical to the right one, but it's not. The one I had only goes in a Skylark or Impala, not a Silverado.

So, I bought the truck used from a Ford dealer last winter. I took it in to get fixed for the intermittent problem as soon as I bought it, because the truck came with an aftermarket warranty - I didn't buy it, it just came with it. Having the work done there would result in a lower out of pocket expense for me. Anyway, the FORD dealer is the one that put the wrong part in and it ended up costing me almost $300 because it wasn't covered under the warranty.

so now, I'm wondering if I can get my money back for their error. I know it's been almost a year, but I didn't feel like going back as I couldn't afford another repair if that's what it needed.

Thoughts? Do I have a chance of getting my money back from the dealer?

P.S. The new/correct part works great.

First, I'm glad you got the heater working properly. As far as the dealer, you can try to get money back, but chances are they won't do anything at this point. Maybe they would split the cost with you. Try that if they say no.

Let me know how it goes.