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Today's AC bafoonery

you mean hanging your head out the window while you hope the coolant warms up enough to blow heat out the defrost isnt Standard operating prcedure? :)

a buddy and I went down to SE KS (south of pittsburgh) and it blew his mind how warm it was, as he is from Idaho and it was lucky to be over freezing back there.
 
CRAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAP!

I got it back together on the 16th and every aspect on the environmentals worked. This morning? No fan in any setting. I can hear the flapper valves moving as I switch from vent/defog but no fan.

Anyone here abandon all hope and just run a hot wire through a rheostat and on to the fan?
 
Have you tried changing the Low Pressure switch?

It won't help the fan but it will help with the cycling.
That is the weakest link in the AC system due to location.
 
If it won't work in any position, then either the fan switch quit, or you lost power to the fan. If it was the fuse then I don't think the A/C control head would even power up. most likely you either have a bad fan motor(very likely as burned out resistors is normally a result of a bad fan motor), or you have a bad connection like behind the glove box.
 
As posted several times you need to change the blower motor out. Resistors burn up because the fan isn't spinning, but, it is taking power. With no cooling the resister coils get hot and pop the thermal fuses rather than burning the truck down. Locked up bearings for example or a foreign object jamming the fan. Bad brushes wouldn't burn the resistors out as there would be no current.

The resister pack isn't used for high speed. You may have burned out the high speed relay from a locked up motor. Not likely, but, does happen.

Likely you burned the resistor pack out again with a bad blower motor. You will need to change both.

Time to send the wife to Starbucks so you can work in a nice garage... :hihi:
 
I have a acdelco blower motor on the way. I'll pull it tonight and check to see if the shunting coils on the blower motor resistor have died but my guess is not. Again, everything was working fine up until this morning. I noticed immediately no defog, cycled through and shut it off...a few seconds on high and maybe one on the rest before off.
 
Having just ordered my new fan for about 110 delivered I came home to pull the old one seeing as Tanner's mom said he couldn't play today (we were going to pull my bed). Before I got at it, I fired up the truck and verified that none of the fan settings worked but that the stepper motors (I guess) were moving the flapper valves to re-direct air and the AC kick on at command. Then I shut it it down and began disassembly.

I've had the ECM out before and even found a clip I'd lost, pulled the bracket came out reasonably easy. I had read not to remove the front two screws just the top two and now know why - they allow the bracket that has vertical slots for the front two to merely be loosened...the bracket kinda rest on them. I pulled the kick plate (well named - one screw on the tread and I kicked it until it came off when the spring clips said uncle. First remotely clever design I've seen on the project. With that and pulling the bolt from below that attaches the steel dash crossmember to the "A" pillar, I had all the room I needed to pull the fan.

Manually, the fan turned...not tremendously easily but it did. I put that squirrel cage in my crotch and jumped the power from the purple wire to the red terminal on the fan and the ground to the crossmember bolt...and the damned thing worked in all speed positions. What the heck? Bad ground?

I'm still going with the new fan. But I have a couple of issues. That connector that everyone talks about - I've saved pictures of the melted terminal - I can't find. Is there not one on a 94 model? Also, in one of the pictures I've included I've placed two circles: one over the purple power wire and ground; the other to...WHAT THE HECK DOES THIS GO TO? Seriously, the two wire pink/white and green/black connector. I can't find a place for it to connect and the fan ran with it disconnected.

Hey, I know I'm over my head. I just need War Wagon to tell me how far. I am going to wait for the new motor to come in Monday to install. In the meantime, I'm going to build a heavy gauge jumper to go from the fan ground terminal to the A pillar bolt. I'll put it all together and see what happens.

I'm desperate for any input.20131226_144726.jpg20131226_145217.jpg
 
If the fan doesn't turn easy it is locking up. (Problem solved.) Gets hot and quits on you. Check the resistor pack or replace it. The plug in the green circle I think is for the VSSB under the ECM tray.

The single red wire next to the purple and black wires I think is the power and connector similar to the 1995's that burn up. As I recall it has a black and red wire in 1994 as a 2 wire connector. Just make sure each connector with 2 wires you can see is in good shape. The extra ground strap from the blower motor has saved me many headaches.
 
The motor did turn under power and all the speeds stepped appropriately when switched so I can't imagine how the fan motor resistor could have been damaged. I found my VSSB - milky white box - not under the ECM on my 94 but buttoned to the dash plastic below and left of the glove box. It had both female connectors filled with male end connectors. I checked every wiring diagram I could find and there is no two wire combination of those colors. I suppose it could be for a feature I don't have.
 
You can just make out one of the connectors to the VSSM in the first photo in the previous posting on the lower left side of the photo...just above the ECM that's sitting on the door of the glove compartment.

Here's a tighter shot of the mystery wires.vssb.jpgwhatisthatthing.jpg
 
Dan Hunter said:
Having just ordered my new fan for about 110 delivered I came home to pull the old one seeing as Tanner's mom said he couldn't play today (we were going to pull my bed). Before I got at it, I fired up the truck and verified that none of the fan settings worked but that the stepper motors (I guess) were moving the flapper valves to re-direct air and the AC kick on at command. Then I shut it it down and began disassembly.

I've had the ECM out before and even found a clip I'd lost, pulled the bracket came out reasonably easy. I had read not to remove the front two screws just the top two and now know why - they allow the bracket that has vertical slots for the front two to merely be loosened...the bracket kinda rest on them. I pulled the kick plate (well named - one screw on the tread and I kicked it until it came off when the spring clips said uncle. First remotely clever design I've seen on the project. With that and pulling the bolt from below that attaches the steel dash crossmember to the "A" pillar, I had all the room I needed to pull the fan.

Manually, the fan turned...not tremendously easily but it did. I put that squirrel cage in my crotch and jumped the power from the purple wire to the red terminal on the fan and the ground to the crossmember bolt...and the damned thing worked in all speed positions. What the heck? Bad ground?

I'm still going with the new fan. But I have a couple of issues. That connector that everyone talks about - I've saved pictures of the melted terminal - I can't find. Is there not one on a 94 model? Also, in one of the pictures I've included I've placed two circles: one over the purple power wire and ground; the other to...WHAT THE HECK DOES THIS GO TO? Seriously, the two wire pink/white and green/black connector. I can't find a place for it to connect and the fan ran with it disconnected.

Hey, I know I'm over my head. I just need War Wagon to tell me how far. I am going to wait for the new motor to come in Monday to install. In the meantime, I'm going to build a heavy gauge jumper to go from the fan ground terminal to the A pillar bolt. I'll put it all together and see what happens.

I'm desperate for any input.View attachment 40440View attachment 40441
Click to expand...

Sounds like you found your problem. if adding a ground wire made it run, then obviously you lost your ground to it.
 
To be clear for anyone searching the thread, the total loss of ALL fan positions was intermittent but did drive the fan replacement. Before installation, I'll compare by hand the free spin of the units and verify function on the trucks harness of the new unit. Photos to follow. Still now idea what the two wire connector is for but I'm willing to close it all back up and not care at this point.
 
Well it's all back together and the a.c. and all fan positions work. With the same amount of effort the old fan spun one time and the one 2.5 times around. With a bonus ground wire in place I hope it keeps working.
 
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