Now pull out the relay again and make a jumper wire and connect the following two relay socket hole together: 87 and 30 and see if the fan comes to life. Be careful it will be high current.

 

You can use a wire or a paper clip

 

No, the wiring to the blower and the blower wiring is good. We are almost there, bare with me for abbout 3 more tests and then we will know what failed

 

Jumped with same paperclip I used yesterday. Nothing

 

If the jumper from 87 to 30 did not start the fan on high then put the jumper only in 87 while you are measuring the voltage, it should be 13.X volts. Then while your still measuring voltage, push the other side of the jumper into 30 and see if the voltage drops

 

Drops to 0

 

From what starting voltage?

 

Starting at 12.9, then 0

 

We are almost there.

1) jumper 87A to 30 and see if you get whatever fan speed is selected in the truck.

2) Pull the relay and the 30A hvac fuse in the U/H fuse box back out and measure the resistance again with the ohm setting of 200 and measure between relay socket 87 and the fuse socket hole that does not have voltage

 

Sorry I meant with the relay still out and also pull the 30A fuse ...