Thanks. I will see if I can get back to the actual ground.

I did try testing the black wire at the relay connector to a common ground but I didn't get anything. When I tested it to the fan connector and got a reading I figured it was alright. Guess I should have posted that it didn't show any response when I tested it to the chassis.

Happen to have a photo of where the ground connection is? Is it connected to the firewall?

 

I saw in another posting you mentioned that the fuel level sender grounds on the back of the cylinder head. Is this the same ground that the blower motor connects to? Reason I ask is for a while the gas gauge was flickering quite a bit.

My interior lights also flicker lightly which I thought might be related to a poor connection somewhere.

 

In post #15, the second test at the relay socket would have found the problem instantly

After reading your posts, I figured out what you did, and I used those results. That's why I had you jump the red wire to the purple wire. The results proved that the ground was faulty. There's more than one way to skin a cat

Sorry, no photos. The bolt goes into the rear of the left cylinder head. There should be several grounds attached there, all with eyelet terminals. The fuel level sending unit is one of them. Check the terminals for corrosion, or possibly a loose bolt. If the engine or cylinder head has been removed, there's a good chance the ground connection didn't get tightened, or maybe not connected at all Fix the ground and you'll be good to go.

 

Really showing my novice-ness here. But is left considered driver side or passenger side?

 

It depends what Country you're in Blazers were available in both left hand drive and right hand drive. That's why we refer to it as left and right, instead of driver and passenger (it eliminates a lot of confusion). Standing at the rear of the vehicle, facing the rear bumper, left is left, right is right

 

awesome... i have been having this same issue except mine is intermittent... sometimes will blow, sometimes will not... i will have to check this stuff out and see where it leads me on mine!

 

Captain Hook you are the man. Thanks a million for helping me out with this. I wasn't able to find the main ground yet but since we got a camping trip coming up this weekend I went with the quick way and spliced in a new cable and grounded to the firewall. Got my fan back!

 

Good, glad you got her going with a cheap fix. Your trip should be a little more comfortable now A proper diagnosis always makes the repair as inexpensive as possible.

The weakest link in an electrical circuit is always the first to fail. Whether it's a fuse, a connection, a motor, or in this case, a ground. High resistance at the ground connection probably caused all of the problems that you had. After you repaired them, the ground became the weakest link again, until it failed completely. Checking voltage drop at each connection would have revealed the cause of the blower motor failing in the beginning.