Fan switch problems, Please help!!

[LockDoc]

-
Is there a ground wire from the blower motor housing to the screw that holds the heater box to the firewall? (short black wire in picture)

LockDoc

[Andy4639]

-After that I decided to go back to the plug on the fan switch and test for voltage.. (NO POWER AT ALL ON ANYTHING when switched on..)

The AC in these trucks is wired totally different from a heater only truck. Is the truck a factory AC truck are did the PO install it??? This could be your problem. If he hooked it up without the correct wiring & components.
The AC trucks have a few more parts to them. The fuse has to be swapped as well.
This link shows the heater only schematic not the AC. It is a great schematic and I refer to it often.
http://67-72chevytrucks.com/vboard/s...185856&page=16

I use the breaker fuse instead of the normal 25 amp fuse. It will heat up and kick off then cool down and come back on. You need to get power to the switch first though.
You stated in your last post you have the AC back running.

Oh well got the aircon back on cold ... oops plug fell off

It want run unless you have the fan switch set to at least the low setting if this is correct then you have power to the switch. ????
Also you said

(NO wiring plug anymore.. P.O. changed to spade connectors..)

This could be the problem. Have you verified the wiring is correct? The wires could be placed wrong.

[Simple10]

I might just buy another fan switch and install it, even though you can hear the air con click when you flick the switch to low and medium, it might be the problem.

[Simple10]

Originally Posted by LockDoc

-
Is there a ground wire from the blower motor housing to the screw that holds the heater box to the firewall? (short black wire in picture)

LockDoc

Yes just looked

[Simple10]

Originally Posted by Andy4639

The AC in these trucks is wired totally different from a heater only truck. Is the truck a factory AC truck are did the PO install it??? This could be your problem. If he hooked it up without the correct wiring & components.
The AC trucks have a few more parts to them. The fuse has to be swapped as well.
This link shows the heater only schematic not the AC. It is a great schematic and I refer to it often.
http://67-72chevytrucks.com/vboard/s...185856&page=16

I use the breaker fuse instead of the normal 25 amp fuse. It will heat up and kick off then cool down and come back on. You need to get power to the switch first though.
You stated in your last post you have the AC back running.

It want run unless you have the fan switch set to at least the low setting if this is correct then you have power to the switch. ????
Also you said


This could be the problem. Have you verified the wiring is correct? The wires could be placed wrong.

That was me who said the plug fell off, when I took the resistor out and replaced it (which done nothing) the weight of it made the plug on the back fall off that’s why I had no cold air.

And when I flick the fan switch to low or medium it doesn’t work but you can hear the aircon click in , so I’m hoping it’s a crap switch now on medium and low, high works fine.

The auto electrician said the switch is fine, Don’t believe him yet. Stay tuned .......

[Andy4639]

The wires that you found off the push button on the back side is the compressor switch. The bottom cable on the controller has to be set for AC which you know and the wires must be connected.

Now with both of these in the right positions the AC should work. By your last statement you don't have low are medium fan speed correct?

Take a close look at the wiring on the switch. I would just about bet it's not correct.

[Simple10]

Originally Posted by Andy4639

The wires that you found off the push button on the back side is the compressor switch. The bottom cable on the controller has to be set for AC which you know and the wires must be connected.

Now with both of these in the right positions the AC should work. By your last statement you don't have low are medium fan speed correct?

Take a close look at the wiring on the switch. I would just about bet it's not correct.

Correct as in the wrong wires on the wrong prong?

It worked when I first bought the truck now and then but
ALWAYS worked on hi ......correct
, no medium or low.

[Andy4639]

It looks like you need to swap the light blue and yellow wires.
Mine is on the left yours is the right side.
Due to our wires not being all the same you may need to just try different combination's and see.

I added my AC to this truck so the brown wire is my orange wire. I did this 30 some years ago.

[Simple10]

Originally Posted by Andy4639

It looks like you need to swap the light blue and yellow wires.
Mine is on the left yours is the right side.
Due to our wires not being all the same you may need to just try different combination's and see.

I added my AC to this truck so the brown wire is my orange wire. I did this 30 some years ago.

Just changed the wires around and it works on low med and hi now......BUT all at the same speed so Im Starting to think the fan switch might be ok?

[Andy4639]

Ok this should help and clear up the wiring colors and where they go.
Looking at our pictures.

Bottom terminal should be the brown wire are the hot feed wire.
Next up from it should be Yellow for low speed
Then beside the yellow is the Light Blue for medium speed.
Then on top the orange wire for high speed.

Now if you look at yours you have the 2 yellow wires going to the same place. This I think is one of the problem's on yours.
You also show no orange wire and the light blue are in the wrong spots.

[Simple10]

Originally Posted by Andy4639

Ok this should help and clear up the wiring colors and where they go.
Looking at our pictures.

Bottom terminal should be the brown wire are the hot feed wire.
Next up from it should be Yellow for low speed
Then beside the yellow is the Light Blue for medium speed.
Then on top the orange wire for high speed.

Now if you look at yours you have the 2 yellow wires going to the same place. This I think is one of the problem's on yours.
You also show no orange wire and the light blue are in the wrong spots.

The thing is it was working fine when I first bought the truck it’s not like the wires have been swapped around or anything, I’m just taking it to an auto electrician and tell them to fix it. I’m done. Thanks for your help anyway

[Simple10]

Originally Posted by Andy4639

Ok this should help and clear up the wiring colors and where they go.
Looking at our pictures.

Bottom terminal should be the brown wire are the hot feed wire.
Next up from it should be Yellow for low speed
Then beside the yellow is the Light Blue for medium speed.
Then on top the orange wire for high speed.

Now if you look at yours you have the 2 yellow wires going to the same place. This I think is one of the problem's on yours.
You also show no orange wire and the light blue are in the wrong spots.

Problem solved, I sold my truck

[Andy4639]

Originally Posted by Simple10

Problem solved, I sold my truck

Man you did get pissed!

Glad you figured it out though!

Thanks for letting us know!

[Sheepdip]

Originally Posted by Simple10

Problem solved, I sold my truck

Actually not solved.....just someone else's problem now.

[Simple10]

Originally Posted by Sheepdip

Actually not solved.....just someone else's problem now.

Well I had to fix 5 problems when I bought it.... now it’s someone else’s turn. Fan still works anyway.... I’m chasing a short bed .... long beds to long for me, and it was a bit to good to throw things in the back of it .