Double check the ground on the firewall. There are a couple (iirc) grounds coming from the dash to the firewall in the engine bay. That would explain why it was working before and not working now.

 

Its working but not blowing out the front vents. it like in defrost so I will have to see why? weird

 

I need to bring this thread back to life regarding the location of that V shaped ground wire... I'm not completely understanding where the locations were for that. Since I had one valve cover stud left in one of the ends I'm sure where that goes but the other two ends, does one of them go to the other valve cover and the last end to the fire wall? I can't find any place on the firewall that looks like a ground came from there. Also I have a second ground wire that looks very similar but with two ends, about 23" long that I can't find a home for (I guess 14 months in pieces was too long for my memory). I'm going to try uploading a picture of these two cables but I'm new here so we'll see how that goes. I've looked at the wiring diagrams but that just doesn't do anything for me.
Thanks,

 

You have a cracked or broken vac line if it only blows out defrost. The resistor provides different fan speeds, when it goes you will only have high. I think the single loop with the(V) and the other ground wire are are attached to the firewall. Looks like three wires coming off firewall..one goes to back behind passenger side valve cover..one goes to valve cover stud and i guess I could go look where third end goes.

 

Ok the v end and the single wire are attached to the firewall just above transmission dipstick. One goes to valve cover,the other to a bolt just below the valve cover on the backside and the other longer single one disappeared back behind motor. Will have to look in daylight from underneath.

 

Thanks, that helps a lot. If you get a chance to locate the end on that long one it would be great!

 

The other end of the single wire ground is on valve cover stud. There is another single ground wire from firewall,on driver side, that goes to bolt just below valve cover. I don't know why there are two going to valve cover on passenger side. I remember finding one hanging a few years back. I asked
a shop and they said, just run it to a valve cover stud . So, guess firewall to engine is the scheme.

 

ReadRam- thanks I got them in place over the weekend.
Tonight I was searching through the service manual for something else and found the diagram for the ground cables. They are in the audio section, page 436 (in case someone in the future needs to see a diagram).

 

Glad to help. Read a short article today that our trucks could benefit from extra ground wires from ignition coil bolts and to passenger side fuel rail.? I don't know if they meant from the body to coil and body to fuel rail support bolt, tho. The jist of it is there aren't enough grounds. I believe everything I read on the web.