Fan switch problems, Please help!!
 

Hey guys, got a quick question.. I've got a 69 Chevy c10.. Factory A/C truck. (It works too!) Since i've owned the truck, the high speed on the fan has never worked.. Driving it one day, the fan stopped blowing entirely and wouldn't turn on. So, i thought "Simple fix!!" BOY, WAS I WRONG!! I am entirely lost on what to do and what to replace.. :waah:

Before everything, i checked the fuses! ALL are good and non-blown..

-First, i got a new fan switch from LMC.. plugged it in, and nothing. (NO wiring plug anymore.. P.O. changed to spade connectors..)
-Secondly, Bought a fan motor relay switch and installed it.. nothing.
-next, i decided to see if the fan motor itself was bad, hooked a wire from battery to terminal and it powered on just fine.. ( no noises or vibrations..)
-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..)

Do any of you guys know what in the world could be causing this? it's 103* outside and i'd love my A/C back!! Maybe a wiring diagram of that area would be fantastic..

Re: Fan switch problems, Please help!!
 

The electrical section has all the wiring schematic's. Sounds like your main wire has come off if you have nothing at the switch.:chevy:

Re: Fan switch problems, Please help!!
 

Check this thread http://67-72chevytrucks.com/vboard/s...d.php?t=658012 or search the board for "fan high speed".... there are quite a few threads about this.

Maybe this will help too
http://67-72chevytrucks.com/vboard/a...1&d=1351177729

Re: Fan switch problems, Please help!!
 

-
Bad resistor....

LockDoc

Re: Fan switch problems, Please help!!
 

I stumbled across this thread after realizing that every other thread just dealt with non-functional high fan speed, but low and medium were fine. I believe that we may have the same problem; high used to be intermittent, and now I have no fan at all. I'm thinking that it's actually the resistor, as LockDoc has suggested. Have you tried this yet? I'm likely going to get into it today, if I can find the resistor. Let me know, thanks.

-James-

Re: Fan switch problems, Please help!!
 

My truck had the same exact issue when I bought it. It is definitely the resistor. Once you find it under the dash, its a cheap and easy fix.

Dont forget to do the heater hose shutoff in the engine bay too. It really helps cool the cab down.

Lost of posts on the site about both issues.

Re: Fan switch problems, Please help!!
 

What was the verdict? My fan works on high but not medium or low now ..... and if I have it on high, when I stop the truck it won’t start again untill I flick the switch to off position...... it’s doing my head in!!

Re: Fan switch problems, Please help!!
 

If the blower only works on high speed you are probably needing a resistor for the heat blower motor circuit. The reason the blower works on high speed but not low or medium is because the resistor is only used on low and medium speeds. The resistor for the heater is located on or inside the heater box on the inside of the truck, depending on if it is A/C or not. A/C resistor would be item #1 inside the heater box in the first picture below, and non-A/C would be item #4 on the outside of the heater box in the second picture. (from the assembly manual)

Pretty easy to change it. Unplug the connector by prying up on it with a small screw driver working from side to side, and remove the two 1/4" screws. I would recommend using a little dielectric grease on the spade terminals before you plug the connector back in.

LockDoc

Re: Fan switch problems, Please help!!
 

Part of the problem to look at is the cable adjustment. Watch how hard you move those levers as they are made out of a pot metal.

Look into the Never Pop Kit available in steel levers.

Re: Fan switch problems, Please help!!
 

I’ll check it out �� toolbox .. thanks ...mines air con

Any specific resistor I have to order or ask for?

Re: Fan switch problems, Please help!!
 

I haven’t taken my old resistor out as yet ... but does it look like https://rover.ebay.com/rover/0/0/0?m...2F192417359832

Re: Fan switch problems, Please help!!
 

Should look like this. #5 in the picture.:chevy:

Re: Fan switch problems, Please help!!
 

From previous pictures it appears you go in through the top through the glove box, is that right?
Thanks this appears to be it?

Re: Fan switch problems, Please help!!
 

Thanks this appears to be it?

Re: Fan switch problems, Please help!!
 

Anyone know the part number ? I can’t find a fan blower resistor on rockauto.com

Re: Fan switch problems, Please help!!
 

Not rock auto but here it is.:chevy:

https://www.classicmuscle.com/392905...hoCqIEQAvD_BwE


Here it is on E bay.:chevy:

https://www.ebay.com/itm/173648437597

Re: Fan switch problems, Please help!!
 

GM #: 3929055
It was a generic switch used in that era on the A/C equipped trucks, Corvettes, Camaros etc

Re: Fan switch problems, Please help!!
 

Thanks for the help guys appreciate it, rock suck I emailed them asking for a link because I couldn’t find it in their category they wouldn’t send me one And said we created it so you could search pretty much ....to keep the cost down.

Re: Fan switch problems, Please help!!
 

Well the part finally turned up......now off to put it in ...... really can’t see how these fail, it’s just a piece of steal with two springs... be interesting to see the one that comes out.

Re: Fan switch problems, Please help!!
 

Let us know if that fixes it or not.

LockDoc

Re: Fan switch problems, Please help!!
 

Waste of time did nothing at all

Re: Fan switch problems, Please help!!
 

Those are just resistors. I didn't look up-thread. Did you change out the relay?

Re: Fan switch problems, Please help!!
 

So over this crap ... put the new Part in didn’t work so i left it in there 20 minutes later the air conditioning doesn’t work at all no more cold

Re: Fan switch problems, Please help!!
 

I know what they are everything has been tested fan switch works on high but not medium or low which indicates it is a resistor when it’s not

Re: Fan switch problems, Please help!!
 

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